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THE history of science has something to offer to 
the humblest intelligence. It is a means of impart- 
ing a knowledge of scientific facts and principles to 
unschooled minds. At the same time it affords a 
simple method of school instruction. Those who 
understand a business or an institution best, as a 
contemporary writer on finance remarks, are those 
who have made it or grown up with it, and the next 
best thing is to know how it has grown up, and then 
watch or take part in its actual working. Generally 
speaking, we know best what we know in its origins. 

The history of science is an aid in scientific research. 
It places the student in the current of scientific 
thought, and gives him a clue to the purpose and 
necessity of the theories he is required to master. It 
presents science as the constant pursuit of truth 
rather than the formulation of truth long since re- 
vealed; it shows science as progressive rather than 
fixed, dynamic rather than static, a growth to which 
each may contribute. It does not paralyze the self- 
activity of youth by the record of an infallible past. 

It is only by teaching the sciences in their histori- 
cal development that the schools can be true to the 
two principles of modern education, that the sciences 
should occupy the foremost place in the curriculum 
and that the individual mind in its evolution should 
rehearse the history of civilization. 

The history of science should be given a larger 
place than at present in general history ; for, as 


Bacon said, the history of the world without a his- 
tory of learning is like a statue of Polyphemus with 
the eye out. The history of science studies the past 
for the sake of the future. It is a story of continu- 
ous progress. It is rich in biographical material. It 
shows the sciences in their interrelations, and saves 
the student from narrowness and premature special- 
ization. It affords a unique approach to the study 
of philosophy. It gives new motive to the study of 
foreign languages. It gives an interest in the ap- 
plications of knowledge, offers a clue to the complex 
civilization of the present, and renders the mind hos- 
pitable to new discoveries and inventions. 

The history of science is hostile to the spirit of 
caste. It shows the sciences rising from daily needs 
and occupations, formulated by philosophy, enrich- 
ing philosophy, giving rise to new industries, which 
react in turn upon the sciences. The history of sci- 
ence reveals men of all grades of intelligence and 
of all social ranks cooperating in the cause of human 
progress. It is a basis of intellectual and social homo- 

Science is international, English, Germans, French, 
Italians, Russians all nations contributing to 
advance the general interests. Accordingly, a survey 
of the sciences tends to increase mutual respect, and 
to heighten the humanitarian sentiment. The history 
of science can be taught to people of all creeds and 
colors, and cannot fail to enhance in the breast of 
every young man, or woman, faith in human progress 
and good-will to all mankind. 

This book is intended as a simple introduction, 
taking advantage of the interests of youth of from 


seventeen to twenty-two years of age (and their in- 
tellectual compeers) in order to direct their atten- 
tion to the story of the development of the sciences. 
It makes no claim to be in any sense complete or 
comprehensive. It is, therefore, a psychological in- 
troduction, having the mental capacity of a certain 
class of readers always in view, rather than a logical 
introduction, which would presuppose in all readers 
both full maturity of intellect and considerable ini- 
tial interest in the history of science. 

I cannot conclude this preface without thanking 
those who have assisted me in the preparation of 
this book Sir William Osier, who read the first 
draft of the manuscript, and aided me with his coun- 
sel ; Dr. Charles Singer, who read all the chapters in 
manuscript, and to whom I am indebted for advice 
in reference to the illustrations and for many other 
valuable suggestions ; the officers of the Bodleian Li- 
brary, whose courtesy was unfailing during the year 
I worked there ; Professor Henry Crew, who helped 
in the revision of two of the chapters by his judicious 
criticism ; Professor J. E. Rush, whose knowledge 
of bacteriology improved the chapter on Pasteur ; 
Professor L. O. Grondahl, who read one of the chap- 
ters relating to the history of physics and suggested 
important emendations ; and Dr. John A. Brashear, 
who contributed valuable information in reference to 
the activities of Samuel Pierpont Langley. I wish to 
express my gratitude also to Miss Florence Bonnet 
for aid in the correction of the manuscript. 

W. LlBBY. 
February 2, 1917. 




















SMITH 129 











PLANE 231 



INDEX 283 


TION. EGYPT, 2500 B.C 6 







MACHINE , 236 





IF you consult encyclopedias and special works in 
reference to the early history of any one of the sci- 
ences, astronomy, geology, geometry, physiology, 
logic, or political science, for example, you will find 
strongly emphasized the part played by the Greeks 
in the development of organized knowledge. Great, 
indeed, as we shall see in the next chapter, are the 
contributions to the growth of science of this highly 
rational and speculative people. It must be conceded, 
also, that the influence on Western science of civili- 
zations earlier than theirs has come to us, to a con- 
siderable extent at least, through the channels of 
Greek literature. 

Nevertheless, if you seek the very origins of the 
sciences, you will inevitably be drawn to the banks 
of the Nile, and to the valleys of the Tigris and the 
Euphrates. Here, in Egypt, in Assyria and Babylonia, 
dwelt from very remote times nations whose genius 
was practical and religious rather than intellectual 
and theoretical, and whose mental life, therefore, was 
more akin to our own than was the highly evolved 
culture of the Greeks. Though more remote in time, 


the wisdom and practical knowledge of Thebes and 
Memphis, Nineveh and Babylon, are more readily 
comprehended by our minds than the difficult spec- 
ulations of Athenian philosophy. 

Much that we have inherited from the earliest 
civilizations is so familiar, so homely, that we simply 
accept it, much as we may light, or air, or water, 
without analysis, without inquiry as to its origin, 
and without full recognition of how indispensable it 
is. Why are there seven days in the week, and not 
eight? Why are there sixty minutes in the hour, and 
why are there not sixty hours in the day? These 
artificial divisions of time are accepted so unquestion- 
ingly that to ask a reason for them may, to an indolent 
mind, seem almost absurd. This acceptance of a week 
of seven days and of an hour of sixty minutes (almost 
as if they were natural divisions of time like day and 
night) is owing to a tradition that is Babylonian in 
its origin. From the Old Testament (which is one 
of the greatest factors in preserving the continuity 
of human culture, and the only ancient book which 
speaks with authority concerning Babylonian history) 
we learn that Abraham, the progenitor of the He- 
brews, migrated to the west from southern Babylonia 
about twenty-three hundred years before Christ. 
Even in that remote age, however, the Babylonians 
had established those divisions of time which are 
familiar to us. The seven days of the week were 
closely associated in men's thinking with the heav- 
enly bodies. In our modern languages they are named 
after the sun, the moon, Mars, Mercury, Jupiter, 
Venus, and Saturn, which from the remotest times 
were personified and worshiped. Thus we see that 


the usage of making seven days a unit of time de- 
pends on the religious belief and astronomical science 
of a very remote civilization. The usage is so com- 
pletely established that by the majority it is simply 
taken for granted. 

Another piece of commonplace knowledge the 
cardinal points of the compass may be accepted, 
likewise, without inquiry or without recognition of its 
importance. Unless thrown on your own resources in 
an unsettled country or on unknown waters, you may 
long fail to realize how indispensable to the practical 
conduct of life is the knowledge of east and west and 
north and south. In this matter, again, the records 
of ancient civilizations show the pains that were taken 
to fix these essentials of science. Modern excava- 
tions have demonstrated that the sides or the corners 
of the temples and palaces of Assyria and Babylo- 
nia were directed to the four cardinal points of the 
compass. In Egypt the pyramids, erected before 
3000 B.C., were laid out with such strict regard to 
direction that the conjecture has been put forward 
that their main purpose was to establish, in a land 
of shifting sands, east and west and north and south. 
That conjecture seems extravagant ; but the fact that 
the Phoenicians studied astronomy merely because of 
its practical value in navigation, the early invention 
of the compass in China, the influence on discovery 
of the later improvements of the compass, make us 
realize the importance of the alleged purpose of the 
pyramids. Without fixed points, without something 
to go by, men, before they had acquired the elements 
of astronomy, were altogether at sea. As they ad- 
vanced in knowledge they looked to the stars for 


guidance, especially to the pole star and the imperish- 
able star-group of the northern heavens. The Egyp- 
tians even developed an apparatus for telling the 
time by reference to the stars a star-clock similar 
in its purpose to the sundial. By the Egyptians, 
also, was carefully observed the season of the year 
at which certain stars and constellations were visible 
at dawn. This was of special importance in the case 
of Sirius, for its heliacal rising, that is, the period 
when it rose in conjunction with the sun, marked 
the coming of the Nile flood (so important in the 
lives of the inhabitants) and the beginning of a 
new year. Not unnaturally Sirius was an object of 
worship. One temple is said to have been so con- 
structed as to face that part of the eastern horizon 
at which this star arose at the critical season of in- 
undation. Of another temple we are told that only 
at sunset at the time of the summer solstice did the 
sun throw its rays throughout the edifice. The fact 
that astronomy in Egypt as in Babylonia, where 
the temples were observatories, was closely associated 
with religion confirms the view that this science was 
first cultivated because of its bearing on the practical 
needs of the people. The priests were the preservers 
of such wisdom as had been accumulated in the 
course of man's immemorial struggle with the forces 
of nature. 

It is well known that geometry had its origin in 
the valley of the Nile, that it arose to meet a practi- 
cal need, and that it was in the first place, as its name 
implies, a measurement of the earth a crude sur- 
veying, employed in the restoration of boundaries 
obliterated by the annual inundations of the river. 


Egyptian geometry cared little for theory. It ad- 
dressed itself to actual problems, such as determin- 
ing the area of a square or triangular field from the 
length of the sides. To find the area of a circular 
field, or floor, or vessel, from the length of the diame- 
ter was rather beyond the science of 2000 B.C* This 
was, however, a practical problem which hacl to be 
solved, even if the solution were not perfect. The prac- 
tice was to square the diameter reduced by one ninth. * 

In all the Egyptian mathematics of which we have 
record there is to be observed a similar practical bent. 
In the construction of a temple or a pyramid not 
merely was it necessary to have regard to the points 
of the compass, but care must be taken to have the 
sides at right angles. This required the intervention 
of specialists, expert " rope-fasteners," who laid off a 
triangle by means of a rope divided into three parts, 
of three, four, and five units. The Babylonians fol- 
lowed much the same practice in fixing a right angle. 
In addition they learned how to bisect and trisect the 
angle. Hence we see in their designs and ornaments 
the division of the circle into twelve parts, a division 
which does not appear in Egyptian ornamentation till 
after the incursion of Babylonian influence. 

There is no need, however, to multiply examples ; 
the tendency of all Egyptian mathematics was, as 
already stated, concerned with the practical solution 
of concrete problems mensuration, the cubical con- 
tents of barns and granaries, the distribution of bread, 
the amounts of food required by men and animals 
in given numbers and for given periods of time, the 
proportions and the angle of elevation (about 52) 
of a pyramid, etc. Moreover, they worked simple 


equations involving one unknown, and had a hiero- 
glyph for a million (the drawing of a man overcome 
with wonder), and another for ten million. 

The Rhind mathematical papyrus in the British 
Museum is the main source of our present knowledge 
of early Egyptian arithmetic, geometry, and of what 
might be called their trigonometry and algebra. It 
describes itself as " Instructions for arriving at the 
knowledge of all things, and of things obscure, and 
of all mysteries." It was copied by a priest about 
1600 B.C. the classical period of Egyptian culture 
from a document seven hundred years older. 

Medicine, which is almost certain to develop in the 
early history of a people in response to their urgent 
needs, has been justly called the foster-mother of 
many sciences. In the records of Egyptian medical 
practice can be traced the origin of chemistry, anat- 
omy, physiology, and botany. Our most definite in- 
formation concerning Egyptian medicine belongs to 
the same general period as the mathematical docu- 
ment to which we have just referred. It is true some- 
thing is known of remoter times. The first physician 
of whom history has preserved the name, I-em-hetep 
(He-who-cometh-in-peace), lived about 4500 B.C. 
Recent researches have also brought to light, near 
Memphis, pictures, not later than 2500 B.C., of surgi- 
cal operations. They were found sculptured on the 
doorposts at the entrance to the tomb of a high official 
of one of the Pharaohs. The patients, as shown in 
the accompanying illustration, are suffering pain, and, 
according to the inscription, one cries out, "Do this 
[and] let me go," and the other, " Don't hurt me 
so ! ' Our most satisfactory data in reference to Egyp- 


tian medicine are derived, however, from the Ebers 
papyrus. This document displays some little knowl- 
edge of the pulse in different parts of the body, of a 
relation between the heart and the other organs, and 
of the passage of the breath to the lungs (and heart). 
It contains a list of diseases. In the main it is a col- 
lection of prescriptions for the eyes, ears, stomach, 
to reduce tumors, effect purgation, etc. There is no 
evidence of a tendency to homeopathy, but mental 
healing seems to have been called into play by the 
use of numerous spells and incantations. Each pre- 
scription, as in medical practice to-day, contains as 
a rule several ingredients. Among the seven hundred 
recognized remedies are to be noted poppy, castor- I 
oil, gentian, colchicum, squills, and many other fa- 
miliar medicinal plants, as well as bicarbonate of soda, 
antimony, and salts of lead and copper. The fat of 
the lion, hippopotamus, crocodile, goose, serpent, and 
wild goat, in equal parts, served as a prescription for 
baldness. In the interests of his art the medical prac- 
titioner ransacked the resources of organic and in- 
organic nature. The Ebers papyrus shows that the 
Egyptians knew of the development of the beetle from 
the egg, of the blow-fly from the larva, and of the 
frog from the tadpole. Moreover, for precision in the 
use of medicaments weights of very small denomi- 
nations were employed. 

The Egyptian embalmers relied on the preserva- 
tive properties of common salt, wine, aromatics, 
myrrh, cassia, etc. By the use of linen smeared with 
gum they excluded all putrefactive agencies. They 
understood the virtue of extreme dry ness in the 
exercise of their antiseptic art. Some knowledge of 


anatomy was involved in the removal of the viscera, 
and much more in a particular method they followed 
in removing the brain. 

In their various industries the Egyptians made 
use of gold, silver, bronze (which on analysis is 
found to consist of copper, tin, and a trace of lead, 
etc.), metallic iron and copper and their oxides, 
manganese, cobalt, alum, cinnabar, indigo, madder, 
brass, white lead, lampblack. There is clear evidence 
that they smelted iron ore as early as 3400 B.C. 
maintaining a blast by means of leather tread-bel- 
lows. They also contrived to temper the metal, and 
to make helmets, swords, lance-points, ploughs, tools, 
and other implements of iron. Besides metallurgy 
they practiced the arts of weaving, dyeing, distilla- 
tion. They produced soap (from soda and oil), 
transparent and colored glass, enamel, and ceramics. 
They were skilled in the preparation of leather. 
They showed aptitude for painting, and for the other 
fine arts. They were expert builders, and possessed the 
engineering skill to erect obelisks weighing hundreds 
of tons. They cultivated numerous vegetables, grains, 
fruits, and flowers. They had many domestic ani- 
mals. In seeking the satisfaction of their practical 
needs they laid the foundation of geometry, botany, 
chemistry (named, as some think, from the Egyptian 
Khem, the god of medicinal herbs), and other sci- 
ences. But their practical achievements far tran- 
scended their theoretical formulations. To all time 
they will be known as an artistic, noble, and reli- 
gious people, who cherished their dead and would 
not allow that the good and beautiful and great 
should altogether pass away. 


Excavations in Assyria and Babylonia, especially 
since 1843, have brought to our knowledge an an- 
cient culture stretching back four or five thousand 
years before the beginning of the Christian era. The I* 
records of Assyria and Babylonia, like those of Egypt, 
are fragmentary and still in need of interpretation. 
Here again, however, it is the fundamental, the in- 
dispensable, the practical forms of knowledge that 
stand revealed rather than the theoretical, specula- 
tive, and purely intellectual. 

By the Babylonian priests the heavens were made 
the object of expert observation as early as 3800 B.C. 
The length of the year, the length of the month, the 
coming of the seasons, the course of the sun in the 
heavens, the movements of the planets, the recur- 
rence of eclipses, comets, and meteors, were studied 
with particular care. One motive was the need of a 
measurement of time, the same motive as underlies 
the common interest in the calendar and almanac. 
It was found that the year contained more than 365 
days, the month (synodic) more than 29 days, 12 
hours, and 44 minutes. The sun's apparent diameter 
was contained 720 times in the ecliptic, that is, in 
the apparent path of the sun through the heavens. 
Like the Egyptians, the Babylonians took special 
note of the stars and star-groups that were to be 
seen at dawn at different times of the year. These 
constellations, lying in the imaginary belt encircling 
the heavens on either side of the ecliptic, bore names 
corresponding to those we have adopted for the signs 
of the zodiac, Balance, Ram, Bull, Twins, Scor- 
pion, Archer, etc. The Babylonian astronomers also 
observed that the successive vernal (or autumnal) 


equinoxes follow each other at intervals of a few sec- 
onds less than a year. 

A second motive that influenced the Babylonian 
priests in studying the movements of the heavenly 
bodies was the hope of foretelling events. The plan- 
ets, seen to shift their positions with reference to the 
other heavenly bodies, were called messengers, or 
angels. The appearance of Mars, perhaps on account 
of its reddish color, was associated in their imagina- 
tions with war. Comets, meteors, and eclipses were 
considered as omens portending pestilence, national 
disaster, or the fate of kings. The fortunes of in- 
dividuals could be predicted from a knowledge of 
the aspect of the heavens at the hour of their birth. 
This interest in astrology, or divination by means of 
the stars, no doubt stimulated the priests to make 
careful observations and to preserve religiously the 
record of astronomical phenomena. It was even es- 
tablished that there is a cycle in which eclipses, solar 
and lunar, repeat themselves, a period (saros) some- 
what more than eighteen years and eleven months. 
Moreover, from the Babylonians we derive some of 
our most sublime religious and scientific concep- 
tions. They held that strict law governs the appar- 
ently erratic movements of the heavenly bodies. 
Their creation myth proclaims : " Merodach next 
arranged the stars in order, along with the sun and 
moon, and gave them laws which they were never to 

mathematical knowledge of the Babylonians is 
related on the one hand to their astronomy and on the 
other to their commercial pursuits. They possessed 
highly developed systems of measuring, weighing, 


and counting processes, which, as we shall see in 
the sequel, are essential to scientific thought. About 
2300 B.C. they had multiplication tables running 
from 1 to 1350, which were probably used in con- 
nection with astronomical calculations. Unlike the 
Egyptians they had no symbol for a million, though 
the " ten thousand times ten thousand " of the Bible 
(Daniel vn : 10) may indicate that the conception 
of even larger numbers was not altogether foreign 
to them. They counted in sixties as well as in tens. 
Their hours and minutes had each sixty subdivisions. 
They divided the circle into six parts and into six- 
times-sixty subdivisions. Tables of squares and cubes 
discovered in southern Babylonia were interpreted 
correctly only on a sexagesimal basis, the statement 
that 1 plus 4 is the square of 8 implying that the first 
unit is 60. As we have already seen, considerable 
knowledge of geometry is apparent in Babylonian 
designs and constructions. 

According to a Greek historian of the fifth cen- 
tury B.C., there were no physicians at Babylon, while 
a later Greek historian (of the first century B.C.) 
speaks of a Babylonian university which had at- 
tained celebrity, and which is now believed to have 
been a school of medicine. Modern research has 
made known letters by a physician addressed to an 
Assyrian king in the seventh century B.C. referring 
to the king's chief physician, giving directions for the 
treatment of a bleeding from the nose from which a 
friend of the prince was suffering, and reporting the 
probable recovery of a poor fellow whose eyes were 
diseased. Other letters from the same general period 
mention the presence of physicians at court. "We have 


even recovered the name (Ilu-bani) of a physician 
who lived in southern Babylonia about 2700 B.C. 
The most interesting information, however, in refer- 
ence to Babylonian medicine dates from the time of 
Hammurabi, a contemporary of the patriarch Abra- 
ham. It appears from the code drawn up in the reign 
of that monarch that the Babylonian surgeons oper- 
ated in case of cataract ; that they were entitled to 
twenty silver shekels (half the sum for which Joseph 
was sold into slavery, and equivalent to seven or 
eight dollars) for a successful operation ; and that in 
case the patient lost his life or his sight as the result 
of an unsuccessful operation, the surgeon was con- 
demned to have his hands amputated. 

The Babylonian records of medicine like those of 
astronomy reveal the prevalence of many superstitious 
beliefs. The spirits of evil bring maladies upon us ; 
the gods heal the diseases that afflict us. The Baby- 
lonian books of medicine contained strange inter- 
minglings of prescription and incantation. The priests 
studied the livers of sacrificial animals in order to 
divine the thoughts of the gods a practice which 
stimulated the study of anatomy. The maintenance 
of state menageries no doubt had a similar influence 
on the study of the natural history of animals. 

The Babylonians were a nation of agriculturists 
and merchants. Sargon of Akkad, who founded the 
first Semitic empire in Asia (3800 B.C.), was brought 
tip by an irrigator, and was himself a gardener. Bel- 
shazzar, the son of the last Babylonian king, dealt 
in wool on a considerable scale. Excavation in the 
land watered by the Tigris and Euphrates tells the 
tale of the money-lenders, importers, dyers, fullers, 


tanners, saddlers, smiths, carpenters, shoemakers, 
stonecutters, ivory-cutters, brickmakers, porcelain- 
makers, potters, vintners, sailors, butchers, engi- 
neers, architects, painters, sculptors, musicians, deal- 
ers in rugs, clothing and fabrics, who contributed to 
the culture of this great historic people. It is not 
surprising that science should find its matrix in so 
rich a civilization. 

The lever and the pulley, lathes, picks, saws, ham- 
mers, bronze operating-lances, sundials, water-clocks, 
the gnomon (a vertical pillar for determining the sun's 
altitude) were in use. Gem-cutting was highly de- 
veloped as early as 3800 B.C. The Babylonians made 
use of copper hardened with antimony and tin, lead, 
incised shells, glass, alabaster, lapis-lazuli, silver, and 
gold. Iron was not employed before the period of con- 
tact with Egyptian civilization. Their buildings were 
furnished with systems of drains and flushes that seem 
to us altogether modern. Our museums are enriched 
by specimens of their handicraft realistic statuary 
in dolerite of 2700 B.C. ; rock crystal worked to the 
form of a plano-convex lens, 3800 B.C.; a beautiful 
silver vase of the period 3950 B.C.; and the head of 
a goat in copper about 4000 B.C. 

Excavation has not disclosed nor scholarship in- 
terpreted the full record of this ancient people in the 
valley of the Tigris and the Euphrates, not far from 
the Gulf of Persia, superior in religious inspiration, 
not inferior in practical achievements to the Egyp- 
tians. Both these great nations of antiquity, however, j 
failed to carry the sciences that arose in connection I 
with their arts to a high degree of generalization*! 
That was reserved for "another people of ancient 
times, namely, the Greeks. 



F. H. Garrison, An Introduction to the History of Medicine. 
H. V. Hilprecht, Excavations in Assyria and Babylonia. 
Max Neuburger, History of Medicine. 
A. H. Sayce, Babylonians and Assyrians. 




No sooner did the Greeks turn their attention to 
the sciences which had originated in Egypt and 
Babylonia than the characteristic intellectual qual- 
ity of the Hellenic genius revealed itself. Thale^ 
(640-546 B.C.), who is usually regarded as the first 
of the Greek philosophers, was the founder of Greek 
geometry and astronomy. He was one of the seven 
" wise men ' *~75f"'~Greece, and might be called the 
Benjamin Franklin of antiquity, for he was inter- 
ested in commerce, famous for political sagacity, and 
honored for his disinterested love of general truth. 
His birthplace was Miletus, a Greek city on the 
coast of Asia Minor. There is evidence that he ac- 
quired a knowledge of Babylonian astronomy. The 
pursuit of commerce carried him to Egypt, and there 
he gained a knowledge of geometry. Not only so, 
but he was able to advance this study by general- 
izing and formulating its truths. For the Egyptians, 
geometry was concerned with surfaces and dimen- 
sions, with areas and cubical contents ; for the Greek, 
with his powers of abstraction, it became a study of 
line and angle. For example, Thales saw that the 
angles at the base of an isosceles triangle are equal, 
and that when two straight lines cut one another the 
vertically opposite angles are equal. However, after 4 
having established general principles, he showed him- 


self capable of applying them to the solution of par- 
ticular problems. In the presence of the Egyptian 
priests, to which class he was solely indebted for in- 
struction, Thales demonstrated a method of measur- 
ing the height of a pyramid by reference to its 
shadow. And again, on the basis of his knowledge 
of the relation of the sides of a triangle to its angles, 
he developed a practical rule for ascertaining the 
distance of a ship from the shore. 

The philosophical mind of Thales laid hold, no 
doubt, of some of the essentials of astronomical sci- 


ence. The particulars usually brought forward to 
prove his originality tend rather to show his indebt- 
edness to the Babylonians. The number of days in 
the year, the length of the synodic month, the rela- 
tion of the sun's apparent diameter to the ecliptic, 
the times of recurrence of eclipses, were matters that 
had long been known to the Babylonians, as well as 
to the Chinese. However, he aroused great interest 
in astronomy among the Greeks by the prediction 
of a solar eclipse. This was probably the eclipse of 
585 B.C., which interrupted a fierce battle between 
the Medes and the Lydians. The advice of Thales 
to mariners to steer by the Lesser Bear, as nearer 
the pole, rather than by the Great Bear, shows also 
that in his astronomical studies as in his geometri- 
cal he was not indifferent to the applications of 
scientific knowledge. 

In fact, some writers maintain that Thales was 
not a philosopher at all, but rather an astronomer 
and engineer. We know very little of his purely 
speculative thought. We do know, however, that he 
arrived at a generalization fantastic to most minds 


that all things jtre water. Attempts have been 
made to add to this statement, and to explain it 
away. Its great interest for the history of thought 
lies in the fact that it is the result of seeking the 
constant in the variable, the unitary principle in the 
multiple phenomena of nature. This abstract and 
general view (though perhaps suggested by the 
Babylonian belief that the world originated in a 
watery chaos, or by the teaching of Egyptian priests) 
was preeminently Greek, and was the first of a 
series of attempts to discover the basis or origin of 
all things. One of the followers of Thales taught 
that air was the fundamental principle ; while Her- 
aclitus, anticipating to some extent modern theories 
of the origin of the cosmos, declared in favor of a 
fiery vapor subject to ceaseless change. Empedo- 
cles, the great philosopher-physician, first set forth 
the doctrine of the four elements earth, air, fire, 
and water. For Democritus indivisible particles or 
atoms are fundamental to all phenomena. It is evi- 
dent that the theory of Thales was a starting point 
for Greek abstract thought, and that his inclination 
to seek out principles and general laws accounts for 
his influence on the development both of philosophy 
and the sciences. 

Evtbagoras, on the advice of Thales, visited Egypt 
in the pursuit of majhematjcg. There is reason to 
believe that he also visited Babylonia. For him and 
his followers mathematics became a philosophy 
almost a religion. They had discovered (by experi- 
menting with the rnonochord, the first piece of 
physical-laboratory apparatus, consisting of a tense 
harpstring with a movable bridge) the effect on the 


tone of the string of a musical instrument when the 
length is reduced by one half, and also that strings 
of like thickness and under equal tension yield har- 
monious tones when their lengths are related as 
1:2, 2:3, 3:4, 4:5. The Pythagoreans drew from 
this the extravagant inference that the heavenly 
bodies would be in distance from the earth as 1, 2, 
3, 4, 5, etc. Much of their theory must seem to the 
modern mind merely fanciful and unsupported spec- 
ulation. At the same time it is only just to this 
school of philosophers to recognize that their assump- 
tion that simple mathematical relationships govern 
the phenomena of nature has had an immense influ- 
ence on the advance of the sciences. Whether their 
fanaticism for number was owing to the influence of 
Egyptian priests or had an Oriental origin, it gave 
to the Pythagoreans an enthusiasm for pure mathe- 
matics. They disregarded the bearing of their sci- 
ence on the practical needs of life. Old problems 
like squaring the circle, trisecting the angle, and 
doubling the cube, were now attempted in a new 
[l spirit and with fresh vigor. The first, second, and 
fourth books of Euclid are largely of Pythagorean 
origin. For jspjid gjgo.n\p,t ( rjr as a science we are also 
indebted to this sect of number-worshipers. One of 
them (Archytas, 428-347 B.C., a friend of Plato) 
was the first to apply geometry to mechanics. We 
see again here, as in the case of Thales, that the 
love of abstract thought, the pursuit of science as 
science, did not interfere with ultimate practical 

JPlato (429-347 B.C.), like many other Greek 
philosophers, traveled extensively, visiting Asia 


Minor, Egypt, and Lower Italy, where Pythagorean 
influence was particularly strong. His chief interest 
lay in speculation. For him there were two worlds, 
thejgogldof sense and the world of ideas. The senses 
deceive usjtherelare, the philosopher should turn his 
back upon the world of sensible impressions, and 
develop the reason. In his Dialogues he outlined a 
course of training and study, the professed object of 
which was to educate a class of philosophers. (Strange 
to say, Plato's curriculum, planned originally for the 
intellectual elite, still dictates in our schools the edu- 
cation of millions of boys and girls whose careers do 
not call for a training merely of the reason.) 

Over the porch of his school, the Academy at 
Athens, were inscribed the words, " Let no one who is . 
unacquainted with geometry enter here." It was not 
because it was useful in everyday life that Plato laid L 
such insistence on this study, but because it increased 
the students' powers of abstraction and trained the ' 
mind to correct and vigorous thinking. From his 
point of view the chief good of geometry is lost unless 
we can through it withdraw the mind from the par- 
ticular and the material. He delighted in clearness 
of conception. His main scientific interest was in 
astronomy and mathematics. We owe to him the 
definition of a line as " length without breadth," and 
the formulation of the axiom, " Equals subtracted 
from equals leave equals." 

Plato had an immediate influence in stimulating: 


mathematical studies, and has been called a maker 
of mathematicians. Euclid, who was active at Alex- 
andria toward the end of the fourth century B.C., was 
not one of Plato's immediate disciples but shared the 


great philosopher's point of view. The story is told 
that one of his pupils, arrived perhaps at the pons 
asinorum, asked, " What do I get by learning these 
things?' Euclid, calling his servant, said, "Give 
him sixpence, since he must make gain out of what 
he learns." Adults were also found, even among the 
nimble-witted Greeks, to whom abstract reasoning 
was not altogether congenial. This is attested by the 
fainiliar story of Ptolemy, King of Egypt, who once 
asked Euclid whether geometry could not be learned 
in some easier way than by studying the geometer's 
book, The Elements. To this the schoolmaster re- 
plied, "There is no royal road to geometry." For 
the academic intelligence abstract and abstruse 
mathematics are tonic and an end in themselves. As 
already stated, their ultimate practical value is also 
immense. One of Plato's associates, working under 
his direction, investigated the curves produced by 
cutting cones of different kinds in a certain plane. 
These curves the ellipse, the parabola, hyperbola 
play a large part in the subsequent history of 
astronomy and mechanics. Another Platonist made 
the first measurement of the earth's circumference. 
Aristotle, the greatest pupil of Plato, was born at 
Stagira in 384 B.C. He came of a family of physi- 
cians, was trained for the medical profession, and 
had his attention early directed to natural phenomena. 
He entered the Academy at Athens about 367 B.C., 
and studied there till the death of Plato twenty 
years later. He was a diligent but, as was natural, 
considering the character of his early education, by 
no means a passive student. Plato said that Aristotle 
reacted against his instructor as a vigorous colt kicks 


the mother that nourishes it. The physician's son 
did not accept without modification the view that the 
philosopher should turn his back upon the things of 
sense. He had been trained in the physical science 
of the time, and believed in the reality of concrete 
things. At the same time he absorbed what he found 
of value in his master's teachings. He thought that* 
science did not consist in a mere study of individual 
things, but that we must pass on to a formulation of 
general principles and then return to a study of the 
concrete. His was a great systematizing intellect, 
which has left its imprint on nearly every depart- 
ment of knowledge. Physical astronomy, physical 
geography, meteorology, physics, chemistry, geology, 
botany, anatomy, physiology, embryology, and zool- 
ogy were enriched by his teaching. It was through 
him that logic, ethics, psychology, rhetoric, aesthetics, 
political science, zoology (especially ichthyology), 
first received systematic treatment. As a great mod- 
ern philosopher has said, Aristotle pressed his way 
through the mass of things knowable, and subjected 
its diversity to the power of his thought. No wonder 
that for ages he was known as " The Philosopher," 
master of those who know. His purpose was to com- 
prehend, to define, to classify the phenomena of or- 
ganic and inorganic nature, to systematize the knowl- 
edge of his own time. 

Twenty years' apprenticeship in the school of Plato 
had sharpened his logical powers and added to his 
stock of general ideas, but had not taught him to dis- 
trust his senses. When we say that our eyes deceive 
us, we really confess that we have misinterpreted the 
data that our sight has furnished. Properly to know 


involves the right use of the senses as well as the 
right use of reason. The advance of science depends 
on the development both of speculation and observa- 
tion. Aristotle advised investigators to make sure of 
the facts before seeking the explanation of the facts. 
|\ Where preconceived theory was at variance with ob- 
jl served facts, the former must of course give way. 
Though it has been said that while Plato was a 
1 dreamer, Aristotle was a thinker, yet it must be ac- 
knowledged in qualification that Plato often showed 
genuine knowledge of natural phenomena in anatomy 
and other departments of study, and that Aristotle 
was carried away at times by his own presuppositions, 
or failed to bring his theories to the test of observa- 
tion. The Stagirite held that the velocity of falling 
bodies is proportional to their weight, that the func- 
tion of the diaphragm is to divide the region of the 
nobler from that of the animal passions, and that the 
brain is intended to act in opposition to the heart, 
the brain being formed of earthy and watery mate- 
rial, which brings about a cooling effect. The theory 
of the four elements the hot, the cold, the moist, 
the dry led to dogmatic statements with little at- 
tempt at verification. From the standpoint of modern 
studies it is easy to point out the mistakes of Aris- 
totle even. Science is progressive, not infallible. 

In his own time he was rather reproached for what 
was considered an undignified and sordid familiarity 
with observed facts. His critics said that having 
squandered his patrimony, he had served in the army, 
and, failing there, had become a seller of drugs. His 
observations on the effects of heat seem to have been 
drawn from the common processes of the home and 


the workshop. Even in the ripening of fruits heat ap- 
pears to him to have a cooking effect. Heat distorts 
articles made of potters' clay after they have been 
hardened by cold. A gain we find him describing the 
manufacture of potash and of steel. He is not disdain- 
ful of the study of the lower animals, but invites us 
to investigate all forms in the expectancy of discover- 
ing something natural and beautiful. In a similar 
spirit of scientific curiosity the Aristotelian work 
The Problems studies the principle of the lever, the 
rudder, the wheel and axle, the forceps, the balance, 
the beam, the wedge, as well as other mechanical 

In Aristotle, in fact, we find a mind exceptionally 
able to form clear ideas, and at the same time to 
observe the rich variety of nature. He paid homage 
both to the multiplicity and the uniformity of na- 
ture, the wealth of the phenomena and the simplicity 
of the law explaining the phenomena. Many general 
and abstract ideas (category, energy, entomology, 
essence, mean between extremes, metaphysics, me- 
teorology, motive, natural history, principle, syllo- 
gism) have through the influence of Aristotle become 
the common property of educated people the world 

Plato was a mathematician and an astronomer 
Aristotle was first and foremost a biologist. His 
books treated the history of animals, the parts of 
animals, the locomotion of animals, the generation of 
animals, respiration, life and death, length and short- 
ness of life, youth and old age. His psychology is, 
like that of the present day, a biological psychology. 
In his contributions to biological science is mani- 



is U 


fested his characteristic inclination to be at once ab- 
stract and concrete. His works display a knowledge 
of over five hundred living forms. He dissected speci- 
mens of fifty different species of animals. One might 
mention especially his minnte knowledge of the sea- 
urchin, of the rnurex (source of the famous Tyrian 
dye), of the chameleon, of the habits of the torpedo, 
the so-called fishing-frog, and nest-making fishes, as 
well as of the manner of reproduction of whales and 
certain species of sharks. One of his chief contribu- 
tions to anatomy is the description of the heart and 
of the arrangement of the blood-vessels. A repug- 
nance to the dissection of the human body seems to 
have checked to some extent his curiosity in refer- 
ence to the anatomy of man, but he was acquainted 
with the structure of the internal ear, the passage 
leading from the pharynx to the middle ear, and the 
two outer membranes of the brain of man. Aristotle's 
genius did not permit him to get lost in the mere de- 
tails of observed phenomena. He recognized resem- 
blances and differences between the various species, 
classified animals as belonging to two large groups, 
distinguished whales and dolphins from fishes, recog- 
nized the family likeness of the domestic pigeon, the 
wood pigeon, the rock pigeon, and the turtle dove. 
He laid down the characteristics of the class of in- 
vertebrates to which octopus and sepia belong. Man 
takes a place in Aristotle's system of nature as a 
social animal, the highest type of the whole series of 
living beings, characterized by certain powers of re- 
call, reason, deliberation. Of course it was not to be 
expected that Aristotle should work out a fully sat- 
isfactory classification of all the varieties of plants 


and animals known to him. Yet his purpose and 
method mark him as the father of natural science. 
He had the eye to observe and the mind to grasp the 
relationships and the import of what he observed. 
His attempt to classify animals according to the na- 
ture of their teeth (dentition) has been criticized as 
unsuccessful, but this principle of classification is still 
of use, and may be regarded as typical of his mind, 
at once careful and comprehensive. 

One instance of Aristotle's combining philosophi- 
cal speculation with acute observation of natural 
phenomena is afforded by his work on generation 
and development. He knew that the transmission of i 
life deserves special study as the predominant func- 
tion of the various species of plants and animals. 
Deformed parents may have well-formed offspring. 
Children may resemble grandparents rather than 
parents. It is only toward the close of its develop- 
ment that the embryo exhibits the characteristics of 
its parent species. Aristotle traced with some care 
the embryological development of the chick from 
the fourth day of incubation. His knowledge of the 
propagation of animals was, however, not sufficient to 
make him reject the belief in spontaneous generation 
from mud, sand, foam, and dew. His errors are 
readily comprehensible, as, for example, in attrib- 
uting spontaneous generation to eels, the habits and 
mode of reproduction of which only recent studies 
have made fully known. In regard to generation, as 
in other scientific fields, the philosophic mind of Aris- 
totle anticipated modern theories, and also raised 
general questions only to be solved by later investi- 
gation of the facts. 



Only one indication need be given of the practical 
Results that flowed from Aristotle's scientific work. 
In one of his writings he has stated that the sphe- 
ricity of the earth can be observed from the fact that 
its shadow on the moon at the time of eclipse is an 
arc. That it is both spherical and small in comparison 
with the heavenly bodies appears, moreover, from 
this, that stars visible in Egypt are invisible in coun- 
tries farther north ; while stars always above the 
horizon in northern countries are seen to set from 
countries to the south. Consequently the earth is not 
only spherical but also not large ; otherwise this phe- 
nomenon would not present itself on so limited a 
change of position on the part of the observer. " It 
seems, therefore, not incredible that the region about 
the Pillars of Hercules [Gibraltar] is connected with 
that of India, and that there is thus only one ocean." 
It is known that this passage from The Philosopher 
influenced Columbus in his undertaking to reach the 
Orient by sailing west from the coast of Spain. 

We must pass over Aristotle's observation of a 
relationship (homology) between the arms of man, 
the forelegs of quadrupeds, the wings of birds, and 
the pectoral fins of fishes, as well as many other 
truths to which his genius for generalization led 

In the field of botany Aristotle had a wide 
knowledge of natural phenomena, and raised general 
questions as to mode of propagation, nourishment, 
relation of plants to animals, etc. His pupil and life- 
long friend, and successor as leader of the Peripa- 
tetic school of philosophy, Tlieophrastus. combined 
a knowledge of mathematics, astronomy, botany, and 


mineralogy. His History of Plants describes about 
five hundred species. At the same time he treats 
the general principles of botany, the distribution of 
plants, the nourishment of the plant through leaf as 
well as root, the sexuality of date palm and terebinth. 
He lays great stress on the uses of plants. His classi- 
fication of plants is inferior to Aristotle's classifica- 
tion of animals. His views in reference to spontaneous 
generation are more guarded than those of his master. 
His work On Stones is dominated by the practical 
rather than the generalizing spirit. It is evidently 
inspired by a knowledge of mines, such as the cele- 
brated Laurium, from which Athens drew its supply 
of silver, and the wealth from which enabled the 
Athenians to develop a sea-power that overmatched 
that of the Persians. Even to-day enough remains of 
the galleries, shafts, scoria, mine-lamps, and other 
utensils to give a clear idea of this scene of ancient 
industry. Theophrastus considered the medicinal 
uses of minerals as well as of plants. 

We have failed to mention Hippocrates (4 6 0-3 70 

^^""'^"^^'^^__ - 
B.C.), the Father of Medicine, in whom is found an 

intimate union of practical science and speculative 
philosophy. We must also pass over such later Greek 
scientists as Aristarchus and Hipparchus who con- 
futed the theorieiTof fythagoras^andrTlato in refer- 
ence to the relative distances of the heavenly bodies 
from the earth. Archimedes of Syracuse demands, 
however, particular consideration. He lived in the 
third century B.C., and has been called tl^^reatest 
mathematician of antiquity. In him we find the de- 
^otion^totfre abstract that marked the Greek intelli- 
gence. He went so far as to say that every kind of 


art is ignoble if connected with daily needs. His in- 
terest lay in abstruse mathematical problems. His 
special pride was in having determined the relative 
dimensions of the sphere and the enclosing cylinder. 
He worked out the principle of the lever. " Give 
me," he said, " a place on which to stand and I will 
move the earth." He approximated more closely 
than the Egyptians the solution of the problem of 
the relation between the area of a circle and the ra- 
dius. His work had practical value in spite of him- 
self. At the request of his friend the King of Sicily, 
he applied his ingenuity to discover whether a cer- 
tain crown were pure gold or alloyed with silver, and 
he hit upon a method which has found many appli- 
cations in the industries. His name is associated 
with the endless screw. In fact, his practical contriv- 
ances won such repute that it is not easy to separate 
the historical facts from the legends that enshroud 
his name. He aided in the defense of his native city 
against the Romans in 212 B.C., and devised war- 
engines with which to repel the besiegers. After the 
enemy had entered the city, says tradition, he stood 
absorbed in a mathematical problem which he had 
diagrammed on the sand. As a rude Roman soldier 
approached, Archimedes cried, "Don't spoil my cir- 
cles," and was instantly killed. The victorious gen- 
eral, however, buried him with honor, and on the 
tomb of the mathematician caused to be inscribed 
the sphere with its enclosing cylinder. The triumphs 
of Greek abstract thought teach the lesson that prac- 
tical men should pay homage to speculation even 
when they fail to comprehend a fraction of it. 



Aristotle, Historia Animalium ; translated by D'A. W. Thomp- 
son. (Vol. iv of the Works of Aristotle Translated into English. 
Oxford: Clarendon Press.) 

A. B. Buckley (Mrs. Buckley Fisher), A Short History of Natural 

G. H. Lewes, Aristotle ; A Chapter in the History of Science. 

T. E. Lones, Aristotle's Researches in Natural Science. 

D'A. W. Thompson, On Aristotle as a Biologist. 

William Whewell, History of the Inductive Sciences. 

Alfred Weber, History of Philosophy. 



VITRUVIUS was a culturedengineer and architect. 
He was employed in the service of the Itoman State 
at the time of Augustus, shortly before the begin- 
ning of the Christian era. He planned basilicas and 
aqueducts, and designed powerful war-engines capa- 
ble of hurling rocks weighing three or four hundred 
pounds. He knew the arts and the sciences, held 
lofty ideals of professional conduct and dignity, and 
was a diligent student of Greek philosophy. 

We know of him chiefly from his ten short books 
on Architecture (De Architecture Libri Decent), 
in which he touches upon much 1 oirthe learning of 
his time. Architecture for Vitruvius is a science 
arising out of many other sciences. Practice and 
theory are its parents. The merely practical man 
loses much by not knowing the background of his 
activities ; the mere theorist fails by mistaking the 
shadow for the substance. Vitruvius in the theoret- 
ical and historical parts of his book draws largely 
on Greek writers ; but in the parts bearing on prac- 
tice he sets forth, with considerable shrewdness, the 
outcome of years of thoughtful professional experi- 
ence. One cannot read his pages without feeling that 
he is more at home in the concrete than in the ab- 
stract and speculative, in describing a catapult than 
in explaining a scientific theory or a philosophy. He 


was not a Plato nor ail Archimedes, but an efficient 
officer of State, conscious of indebtedness to the 
great scientists and philosophers. With a just sense 
of his limitations he undertook to write, not as a lit- 
erary man, but as an architect. His education had 
been mainly professional, but, the whole circle of 
learning being one harmonious system, he had been 
drawn to many branches of knowledge in so far as 
they were related to his calling. 

In the judgment of Vitruvius an architect should 
be a good writer, able to give a lucid explanation of 
his plans, a skillful draftsman, versed in geometry 
and optics, expert at figures, acquainted with history, 
informed in the principles of physics and of ethics, 
knowing something of music (tones and acoustics), 
not ignorant of law, or of hygiene, or of the mo- 
tions, laws, and relations to each other of the heav- 
enly bodies. For, since architecture " is founded upon 
and adorned with so many different sciences, I am 
of opinion that those who have not, from their early 
youth, gradually climbed up to the summit, cannot 
without presumption, call themselves masters of it." 

Vitruvius was far from sharing the view of Archi- 
medes that art which was connected with the satis- 
faction of daily needs was necessarily ignoble and 
vulgar. On the contrary, his interest centered in the 
practical ; and he was mainly concerned with scien- 
tific theory by reason of its application in the 
Geometry helped him plan a staircase ; s 
of tones was necessary in discharging catapults ; law 
dealt with boundary-lines, sewage-disposal, and con- 
tracts ; hygiene enabled the architect to show a Hip- 
pocratic wisdom in the choice of building-sites with 


due reference to airs and waters. Vitruvius had the 
Roman practical and regulative genius, not the ab- 
stract and speculative genius of Athens. 

The second book begins with an account of dif- 
ferent philosophical views concerning the origin of 
matter, and a discussion of the earliest dwellings of 
man. Its real theme, however, is building-material 
brick, sand, lime, stone, concrete, marble, stucco, 
timber, pozzolano. In reference to the last (vol- 
canic ash combined with lime and rubble to form a 
cement) Vitruvius writes in a way that indicates a 
discriminating knowledge of geological formations. 
Likewise his discussion of the influence of the Apen- 
nines on the rainfall, and, consequently, on the tim- 
ber of the firs on the east and west of the range, 
shows a grasp of meteorological principles. His real 
power to generalize is shown in connection with his 
specialty, in his treatment of the sources of build- 
ing-material, rather than in his consideration of the 
origin of matter. 

Similarly the fifth book begins with a discussion 
of the theories of Pythagoras, but its real topic is 
public buildings fora, basilicas, theaters, baths, 
palaestras, harbors, and quays. In the theaters bronze 
vases of various sizes, arranged according to Pythag- 
orean musical principles, were to be used in the 
auditorium to reinforce the voice of the actor. (This 
recommendation was misunderstood centuries later, 
when Vitruvius was considered of great authority, 
and led to the futile practice of placing earthenware 
jars beneath the floors of church choirs.) According 
to our author, " The voice arises from flowing breath, 
sensible to the hearing through its percussion on 


the air." It is compared to the wavelets produced by 
a stone dropped in water, only that in the case of 
sound the waves are not confined to one plane. This 
generalization concerning the nature of sound was 
probably not original, however ; it may have been 
suggested to Vitruvius by one of the Aristotelian 

The seventh book treats of interior decoration 
mosaic floors, gypsum mouldings, wall painting, 
white lead, red lead, verdigris, mercury (which may 
be used to recover gold from worn-out pieces of em- 
broidery), encaustic painting with hot wax, colors 
(black, blue, genuine and imitation murex purple). 
The eighth book deals with water and with hydraulic 
engineering, hot springs, mineral waters, leveling 
instruments, construction of aqueducts, lead and 
clay piping. Vitruvius was not ignorant of the fact 
that water seeks its own level, and he even argued 
that air must have weight in order to account for 
the rise of water in pumps. In his time it was more 
economical to convey the hard water by aqueducts 
than by such pipes as could then be constructed. 
The ninth book undertakes to rehearse the elements 
of geometry and astronomy the signs of the zodiac, 
the sun, moon, planets, the phases of the moon, the 
mathematical divisions of the gnomon, the use of the 
sundial, etc. One feels in reading Vitruvius that his 
purpose was to turn to practical account what he had 
gained from the study of the sciences ; and, at the 
same time, one is convinced that his applications tend 
to react on theoretical knowledge, and lead to new 
insights through the suggestion of new problems. 

The tenth book of the so-called De Architectures 


is concerned with machinery windmills, windlasses, 
axles, pulleys, cranes, pumps, fire-engines, revolving 
spiral tubes for raising water, wheels for irrigation 
worked by water-power, wheels to register distance 
traveled by land or water, scaling-ladders, batter- 
ing-rams, tortoises, catapults, scorpions, and ballistae. 
On the subject of war-engines Vitruvius speaks with 
special authority, as he had served, probably as mili- 
tary engineer, under Julius Caesar in 46 B.C., and 
had been appointed superintendent of ballistae and 
other military engines in the tune of Augustus. It 
was to the divine Emperor that his book was dedi- 
cated as a protest against the administration of 
Roman public works. In its pages we see reflected 
the life of a nation employed in conquering and 
ruling the world, with a genius more distinguished 
for practical achievement than for theory and specu- 
lation. Its author is truly representative of Roman 
culture, for nearly everything that Rome had of a 
scientific and intellectual sort it drew from Greece, 
and it selected that part of Greek wisdom that minis- 
tered to the daily needs of the times. In his work 
on architecture, Vitruvius shows himself a diligent 
and devoted student of the sciences in order that 
he may turn them to account in his own department 
of technology. 

If you glance at the study of mathematics, astron- 
omy, and medicine among the Romans prior to the 
time of Greek influence, you find that next to noth- 
ing had been accomplished. Their method of field 
measurement was far less developed than the ancient 
Egyptian geometry, and even for it (as well as for 
their system of numerals) they were indebted to 


the Etruscans. The history of astronomy has nothing 
to record of scientific accomplishment on the part of 
the Romans. They reckoned time by months, and in 
the earlier period kept a rude tally of the years by 
driving nails into a statue of Janus, the ancient 
sun-god. As we shall see, they were unable to regu- 
late the calendar. Again, so far were they from con- 
tributing to the development of medicine that they 
had no physicians for the six hundred years preced- 
ing the coming of Greek science. A medical slave 
acted as overseer of the family health, and disease 
was combated in primitive fashion by prayers and 
offerings to various gods, who were supposed to fur- 
nish general health or to influence the functions of 
the different parts of the body. So rude was the na- 
tive culture of the Romans that it is doubtful whether 
they had any schools before the advent of Greek learn- 
ing. The girls were trained by their mothers, the 
boys either by their fathers or by some master to 
whom they were apprenticed. 

UThe Greeks were conquered by the Romans in 
46B.C., but before that time Roman life and insti- 
tutions had been touched by Hellenic culture. Cato 
the Censor (who died in 149 B.C.) and other con- 
servatives tried in vain to resist the invasion of 
Greek science, philosophy, and refinement. After the 
conquest of Greece the master became pupil, and 
the conqueror was taken captive. The Romans, 
however, never rose to preeminence in science or the 
fine arts. >A further development in technology cor- 
respondedmore closely to their national needs, and 
in this field they came undoubtedly to surpass the 
Greeks. Bridges, ships, military roads, war-engines, 


aqueducts, public buildings, organization of the 
State and the army, the formulation of legal proce- 
dure, the enactment and codification of laws, were 
necessary to secure and maintain the Empire. The 
use in building construction of a knowledge of the 
right-angled triangle as well as other matters known 
to the Egyptians and Babylonians, and Archimedes' 
method of determining specific gravity were of pecul- 
iar interest to the practical Romans. 

Julius Casar, 102-44 B.C., instituted a reform of 
the calendar. This was very much needed, as the 
Romans were eighty-five days out of their reckoning, 
and the date for the spring equinox, instead of com- 
ing at the proper time, was falling in the middle of 
winter. An Alexandrian astronomer (Sosigenes) as- 
sisted in establishing the new (Julian) calendar. The 
principle followed was based on ancient Egyptian 
practice. Among the 365 days of the year was to 
be inserted, or intercalated, every fourth year an 
extra day. This the Romans did by giving to two 
days in leap-year the same name ; thus the sixth day 
before the first of March was repeated, and leap- 
year was known as a bissextile year. Caesar, trained 
himself in the Greek learning and known to his con- 
temporaries as a writer on mathematics and astron- 
omy, also planned a survey of the Empire, which was 
finally carried into execution by Augustus. 

There is evidence that the need of technically 
trained men became more and more pressing as the 
Empire developed. At first there were no special 
teachers or schools. Later we find mention of teach- 
ers of architecture and mechanics. Then the State 
came to provide classrooms for technical instruction 


and to pay the salaries of the teachers. Finally, 
in the fourth century A.D., further measures were 
adopted by the State. The Emperor Constantine 
writes to one of his officials : " We need as many en- 
gineers as possible. Since the supply is small, induce 
to begin this study youths of about eighteen years 
of age who are already acquainted with the sciences 
required in a general education. Relieve their par- 
ents from the payment of taxes, and furnish the stu- 
dents with ample means." 

Pliny the Elder (23-79 A.D.), in the encyclopedic 
work which he compiled under the title Natural 
History, drew freely on hundreds of Greek and 
Latin authors for his facts and fables. In the selec- 
tion that he made from his sources can be traced, as 
in the work of Vitruvius and other Latin writers, the 
tendency to make the sciences subservient to the 
arts. For example, the one thousand species of plants 
of which he makes mention are considered from the 
medicinal or from the economic point of view. It was 
largely in the interest of tlieir-pratrtical uses"that the 
Roman regarded both plants and animals ; his chief 
motive was not a disinterested love of truth. Pliny 
thought that each plant had its special virtue, and 
much of his botany is applied botany. So compre- 
hensive a work as the Natural History was sure to 
contain interesting anticipations of modern science. 
Pliny held that the earth hovers in the heavens up- 
held by the air, that its sphericity is proved by the 
fact that the mast of a ship approaching the land 
is visible before the hull comes in sight. He also 
taught that there are inhabitants on the other side of 
the earth (antipodes), that at the time of the winter 


solstice the polar night must last for twenty-four 
hours, and that the moon plays a part in the produc- 
tion of the tides. Nevertheless, the whole book is 
permeated by the idea that the purpose of nature is 
to minister to the needs of man. 

It further marks the practical spirit among the 
Romans that a work on agriculture by a Carthagin- 
ian (Mago) was translated by order of the Senate. 
Cato (234-149 B.C.), so characteristically Roman 
in his genius, wrote (JDe, lie Rustled) concerning 
grains and the cultivation of fruits. Columella wrote 
treatises on agriculture and forestry. Among the 
technical writings of Varro besides the book on agri- 
culture, which is extant, are numbered works on 
law, mensuration, and naval tactics. 

It was but natural that at the time of the Roman 
Empire there should be great advances in medical 
science. A Roman's interest in a science was keen 
when it could be proved to have immediate bearing 
on practical life. The greatest physician of the time, 
however, was a Greek. Qalen (131-201 A.D.), who 
counted himself a disciple of Hippocrates, began to 
practice at Rome at the age of thirty-three. He was 
the only experimental physiologist before the time 
of Harvey. He studied the vocal apparatus in the 
larynx, and understood the contraction and relax- 
ation of the muscles, and, to a considerable extent, 
the motion of the blood through the heart, lungs, and 
other parts of the body. He was a vivisector, made 
sections of the brain in order to determine the func- 
tions of its parts, and severed the gustatory, optic, 
and auditory nerves with a similar end in view. His 
dissections were confined to the lower animals. Yet 


his works on human anatomy and physiology were 
authoritative for the subsequent thirteen centuries. 
It is difficult to say how much of the work and 
credit of this practical scientist is to be given to the 
race from which he sprang and how much to the 
social environment of his professional career. (In 
the ruins of Pompeii, destroyed in 79 A.D., have 
been recovered some two hundred kinds of surgical 
instrument, and in the later Empire certain depart- 
ments of surgery developed to a degree not sur- 
passed till the sixteenth century.) If it is too much 
to say that the Roman environment is responsible 
for Galen's achievements, we can at least say that 
it was characteristic of the Roman people to wel- 
come such science as his, capable of demonstrating 
its utility. 

Dioscorides was also a Greek who, long resident 
at Rome, applied his science in practice. He knew 
six hundred different plants, one hundred more than 
Theophrastus. The latter laid much stress, as we have 
seen in the preceding chapter, on the medicinal prop- 
erties of plants, but in this respect he was outdone 
by Dioscorides (as well as by Pliny). Theophrastus 
was the founder of the science of botany, Dioscor- 
ides the founder of materia medica. 

Quintilian, born in Spain, spent the greater part 
of his life as a teacher of rhetoric in Rome. He val- 
ued the sciences, not on their own account, but as they 
might subserve the purposes of the orator. Music, 
astronomy, logic, and even theology, might be ex- 
ploited as aids to public speech. In the time of Quin- 
tilian (first century A.D.), as in our own, oratory was 
considered one of the great factors in a young man's 


success; mock debating contests were frequent, and 
the periods of the future orators reverberated among 
the seven hiDs of Rome. To him our schools are also 
indebted for the method of teaching foreign languages 
by declensions, conjugations, vocabularies, formal 
rhetoric and annotations. He considered ethics the 
most valuable part of philosophy. 

In fact, it would not be pressing our argument un- 
duly to say that, so far as the minds of the Romans 
turned to speculation, it was the tendency to pracJLk 
cal philosophy Epicureanism or Stoicism that 
was most characteristic. This was true even of Lu- 


cretius (98-55 B.C.), author of the noble poem con- 
cerning the Nature of Things (I)e, Rerum Natura). 
In this work he writes under the inspiration of Greek 
philosophy. His model was a poem by Empedocles 
on Nature, the grand hexameters of which had fasci- 
nated the Roman poet. The distinctive feature of the 
work of Lucretius is the purpose, ethical rather than 
speculative, to curb the ambition, passion, luxury of 
those hard pagan times, and likewise to free the souls 
of his countrymen from the fear of the gods and the 
fear of death, and to replace superstition by peace of 
mind and purity of heart. 

From the work on Physical Science ( Qucestionum 
Naturalium, Librl Septem) of Seneca, the tutor of 
Nero, we learn that the Romans made use of globes 
filled with water as magnifiers, employed hothouses 
in their highly developed horticulture, and observed 
the refraction of colors by the prism. At the same 
time the book contains interesting conjectures in 
reference to the relation of earthquakes and vol- 
canoes, and to the fact that comets travel in fixed 


orbits. In the main, however, this work is an attempt 
to find a basis for ethics in natural phenomena. Sen- 
eca was a Stoic, as Lucretius was an Epicurean, 

When we glance back at the culture, or cultures, 
of the great peoples of antiquity, Egyptian, Baby- 
lonian, Greek, and Roman, that which had its center 
on the_banks of the Tiber_ojfers the closest analogy 
to our own. Among English-speaking peoples as 
among the Romans there is noticeable a certain con- 
tempt for scientific studies strangely mingled with 
an inclination to exploit all theory in the interest of 
immediate application. An English author, writing 
in 1834, remarks that the Romans, eminent in war, 
in polite literature, and civil policy, showed at all 
times a remarkable indisposition to the pursuit of 
mathematical and physical science. Geometry and 
astronomy, so highly esteemed by the Greeks, were 
not merely disregarded by the Italians, but even con- 
sidered beneath the attention of a man of good birth 
and liberal education ; they were imagined to partake 
of a mechanical, and therefore servile, character. " The 
results were seen to be made use of by the mechani- 
cal artist, and the abstract principles were therefore 
supposed to be, as it were, contaminated by his touch. 
This unfortunate peculiarity in the taste of his coun- 
trymen is remarked by Cicero. And it may not be 
irrelevant to inquire, whether similar prejudices do 
not prevail to some extent even among ourselves." 
To Americans also must be attributed an impatience 
of theory as theory, and a predominant interest in the 
applications of science. 



Lucretius, The Nature of Things ; translated by H. A. J. Munro. 
Pliny, Natural History ; translated by Philemon Holland. 
Professor Baden Powell, History of Natural Philosophy. 
Seneca, Physcial Science ; translated by John Clarke. 
Vitruvius, Architecture ; translated by Joseph Gwilt, 1826. 
Vitruvius, Architecture ; translated by Professor M. H. Morgan, 




LEARNING has very often and very aptly been 
compared to a torch passed from hand to hand. By 
the written sign or spoken word it is transmitted 
from one person to another. Very little advance in 
culture could be made even by the greatest man of 
genius if he were dependent, for what knowledge he 
might acquire, merely on his own personal observa- 
tion. Indeed, it might be said that exceptional men- 
tal ability involves a power to absorb the ideas of 
others, and even that the most original people are 
those who are able to borrow the most freely. 

In recalling the lives of certain great men we may 
at first be inclined to doubt this truth. How shall 
we account for the part played in the progress of 
civilization by the rustic Burns, the village-bred 
Shakespeare, or by Lincoln the frontiersman? When, 
however, we scrutinize the case of any one of these, 
we discover, of course, exceptional natural endow- 
ment, susceptibility to mental influence, remarkable 
powers of acquisition, but no ability to produce any- 
thing absolutely original. In the case of Lincoln, 
for example, we find that in his youth he was as 
distinguished by diligence in study as by physical 
stature and prowess. After he withdrew from 
school, he read, wrote, and ciphered (in the inter- 
vals of manual work) almost incessantly. He read 


everything he could lay hands on. He copied out 
what most appealed to him. A few books he read 
and re-read till he had almost memorized them. 
What constituted his library? The Bible, *sE sop's 
Fables, Robinson Crusoe, The Pilgrim's Progress, 
a Life of Washington, a History of the United 
States. These established for him a vital relation 
with the past, and laid the foundations of a demo- 
cratic culture ; not the culture of a Chesterfield, to 
be sure, but something immeasurably better, and 
none the less good for being almost universally ac- 
cessible. Lincoln developed his logical powers con- 
ning the dictionary. Long before he undertook the 
regular study of the law, he spent long hours poring 
over the revised statutes of the State in which he 
was living. From a book he mastered with a pur- 
pose the principles of grammar. In the same spirit 
he learned surveying, also by means of a book. 
There is no need to ignore any of the influences 
that told toward the development of this great 
statesman, the greatest of English-speaking orators, 
but it is evident that remote as was his habitation 
from all the famous centers of learning he was, never- 
theless, early immersed in the current of the world's 
best thought. 

Similarly, in the history of science, every great 
thinker has his intellectual pedigree. Aristotle was 
the pupil of Plato, Plato was the disciple of Soc- 
rates, and the latter's intellectual genealogy in turn 
can readily be traced to Thales, and beyond to 
Egyptian priests and Babylonian astronomers. 

The city of Alexandria, founded by the pupil of 
Aristotle in 332 B.C., succeeded Athens as the center 


of Greek culture. On the death of Alexander the 
Great, Egypt was ruled by one of his generals, 
Ptolemy, who assumed the title of king. This mon- 

~, 1 ' -^.-. 

arch, though often engaged in war, found time to 
encourage learning, and drew to his capital scholars 
and philosophers from Greece and other countries. 
He wrote himself a history of Alexander's cam- 
paigns, and instituted the famous library of Alexan- 
dria. This was greatly developed (and supplemented 
with schools of science and an observatory) by his 
son Ptolemy Philadelphus, a prince distinguished by 
his zeal in promoting the good of the human species. 
He collected vast numbers of manuscripts, had 
strange animals brought from distant lands to Alex- 
andria, and otherwise promoted scientific research. 
This movement was continued under Ptolemy III 
(246-221 B.C.). 

Something has already been said of the early as- 
tronomers and mathematicians of Alexandria. The 
scientific movement of the later Alexandrian period 
found its consummation in the geographer, astrono- 
mer, and mathematician Claudius Ptolemy (not to 
be confused with the rulers of that tialne). He was 
most active 127-151 A.D., and is best known by his 
work the Syntaxis, which summarized what was 
known in astronomy at that time. Ptolemy drew up 
a catalogue of 1080 stars based on the earlier work 
of Hipparchus. He followed that astronomer in 
teaching that the earth is the center of the move- 
ment of the heavenly bodies, and this geocentric 
system of the heavens became known as the Ptole- 
maic system of astronomy. To Hipparchus and 
Ptolemy we owe also the beginnings of the science 



of trigonometry. The Syntaxis sets forth his method 
of drawing up a table of chords. For example, the 
side of a hexagon inscribed in a circle is equal to 
the radius, and is the chord of 60, or of the sixth 
part of the circle. The radius is divided into sixty 
equal parts, and these again divided and subdivided 
sexagesimally. The smaller divisions and the sub- 
divisions are known as prime minute parts and sec- 
ond minute parts (partes minutce primce and paries 
minutes secundce), whence our terms " minute " and 
" second." The sexagesimal method of dividing the 
circle and its parts was, as we have seen in the first 
chapter, of Babylonian origin. 

Ptolemy was the last of the great Greek astrono- 
mers. In the fourth century and at the beginning 
of the fifth, Theon and his illustrious daughter Hy- 
patia commented on and taught the astronomy of 
Ptolemy. In the Greek schools of philosophy Plato's 
doctrine of the supreme reality of the invisible world 
was harmonized for a time with Christian mysticism, 
but these schools were suppressed at the beginning 
of the sixth century. The extinction of scientific and 
of all other learning seemed imminent. 

What were the causes of this threatened break in 
the historical continuity of science ? They were too 
many and too varied to admit of adequate statement 
here. From the latter part of the fourth century the 
Roman Empire had been overrun by the Visigoths, 
the Vandals, the Huns, the Ostrogoths, the Lom- 
bards, and other barbarians. Even before these incur- 
sions learning had suffered under the calamity of 
war. In the time of Julius Caesar the larger of the 
famous libraries of Alexandria, containing, it is com- 


puted, some 490,000 rolls, caught fire from ships 
burning in the harbor, and perished. This alone 
involved an incalculable setback to the march of 
scientific thought. 

Another influence tending to check the advance of 
the sciences was the clash between Christian and Pagan 
ideals. To many of the bishops of the Church the aims 
and pursuits of science seemed vain and trivial when 
compared with the preservation of purity of charac- 
ter or the assurance of eternal felicity. Many were 
convinced that the end of the world was at hand, 
and strove to fix their thoughts solely on the world 
to come. Their austere disregard of this life found 
some support in a noble teaching of the Stoic phi- 
losophy that death itself is no evil to the just man. 
The early Christian teachers held that the body 
should be mortified if it interfered with spiritual 
welfare. Disease is a punishment, or a discipline to 
be patiently borne. One should choose physical un- 
cleanliness rather than run any risk of moral con- 
tamination. It is not impossible for enlightened 
people at the present time to assume a tolerant atti- 
tude toward the worldly Greeks or the other-worldly 
Christians. At that time, however, mutual antipathy 
was intense. The long and cruel war between science 
and Christian theology had begun. 

Not all the Christian bishops, to be sure, took a 
hostile view of Greek learning. Some regarded the 
great philosophers as the allies of the Church. Some 
held that churchmen should study the wisdom of the 
Greeks in order the better to refute them. Others 
held that the investigation of truth was no longer 
necessary after mankind had received the revelation 


of the gospel. One of the ablest of the Church Fa- 
thers regretted his early education and said that it 
would have been better for him if he had never heard of 
Democritus. The Christian writer Lactantius asked 
shrewdly whence atoms came, and what proof there 
was of their existence. He also allowed himself to 
ridicule the idea of the antipodes, a topsy-turvy 
world of unimaginable disorder. In 389 A.D. one of 
the libraries at Alexandria was destroyed and its 
books were pillaged by the Christians. In 415 
Hypatia, Greek philosopher and mathematician, was 
murdered by a Christian mob. In 642 the Arabs 
having pushed their conquest into northern Africa 
gained possession of Alexandria. The cause of learn- 
ing seemed finally and irrecoverably lost. 

The Arab conquerors, however, showed themselves 
singularly hospitable to the culture of the nations 
over which they had gained control. Since the time 
of Alexander there had been many Greek settlers in 
the larger cities of Syria and Persia, and here learn- 
ing had been maintained in the schools of the Jews 
and of a sect of Christians (Nestorians), who were 
particularly active as educators from the fifth century 
to the eleventh. The principal Greek works on sci- 
ence had been translated into Syrian. Hindu arith- 
metic and astronomy had found their way into Persia. 
By the ninth century all these sources of scientific 
knowledge had been appropriated by the Arabs. 
Some fanatics among them, to be sure, held that 
one book, the Koran, was of itself sufficient to in- 
sure the well-being of the whole human race, but 
happily a more enlightened view prevailed. 

In the time of Harun Al-Rashid (800 A.D.), and 



his son, the Caliphate of Bagdad was the center 
of Arab science. ^Mathematics and astronomy were 
especially cultivated ; an observatory was established ; 
and the work of translation was systematically car- 
ried on by a sort of institute of translators, who ren- 
dered the writings of Aristotle, Hippocrates, Galen, 
Euclid, Ptolemy, and other Greek scientists, into Ara- 
bic. The names of the great Arab astronomers and 
mathematicians are not popularly known to us ; their 
influence is greater than their fame. One of them 
describes the method pursued by him in the ninth 
century in taking measure of the circumference of 
the earth. A second developed a trigonometry of 
sines to replace the Ptolemaic trigonometry of chords. 
A third made use of the so-called Arabic (really 
Hindu) system of numerals, and wrote the first work 
on Algebra under that name. In this the writer did 
not aim at the mental discipline of students, but 
sought to confine himself to what is easiest and most 
useful in calculation, " such as men constantly re- 
quire in cases of inheritance, legacies, partition, law- 
suits, and trade, and in all their dealings with one 
another, or where the measuring of lands, the dig- 
ging of canals, geometrical computation, and other 
objects of various sorts and kinds are concerned." 

In the following centuries Arab institutions of 
higher learning were widely distributed and the flood- 
tide of Arab science was borne farther west. At 
Cairo about the close of the tenth century the first 
accurate records of eclipses were made, and tables 
were constructed of the motions of the sun, moon, 
and planets. Here as elsewhere the Arabs displayed 
ingenuity in the making of scientific apparatus, celes- 


:ial globes, sextants of large size, quadrants of vari- 
ous sorts, and contrivances from which in the course 
of time were developed modern surveying instruments 
for measuring horizontal and vertical angles. Before 
the end of the eleventh century an Arab born at 
Cordova, the capital of Moorish Spain, constructed 
the Toletan Tables. These were followed in 1252 
by the publication of the Alphonsine Tables, an 
event which astronomers regard as marking the 
dawn of European science. 

Physics and chemistry, as well as mathematics and 
astronomy, owe much in their development to the 
Arabs. An Arabian scientist of the eleventh century 
studied the phenomena of the reflection and refrac- 
tion of light, explained the causes of morning and 
evening twilight, understood the magnifying power 
of lenses and the anatomy of the human eye. Our 
use of the terms retina, cornea, and vitreous humor 
may be traced to the translation of his work on op- 
tics. The Arabs also made fair approximations to 
the correct specific weights of gold, copper, mercury, 
and lead. Their alchemy was closely associated with 
metallurgy, the making of alloys and amalgams, and 
the handicrafts of the goldsmiths and silversmiths. 
The alchemists sought to discover processes whereby 
one metal might be transmuted into another. Sul- 
phur affected the color and substance. Mercury was 
supposed to play an important part in metal trans- 
mutations. They thought, for example, that tin con- 
tained more mercury than lead, and that the baser, 
more unhealthy metal might be converted into the 
nobler and more healthy by the addition of mercury. 
They even sought for a substance that might effect 


all transmutations, and be for mankind a cure for 
all ailments, even that of growing old. The writings 
that have been attributed to Geber show the advances 
that chemistry made through the experiments of the 
Arabs. They produced sulphuric and nitric acids, 
and aqua regia, able to dissolve gold, the king of 
metals. They could make use of wet methods, and 
form metallic salts such as silver nitrate. Labora- 
tory processes like distilling, filtering, crystallization, 
sublimation, became known to the Europeans through 
them. They obtained potash from wine lees, soda 
from sea-plants, and from quicksilver the mercuric 
oxide which played so interesting a part in the later 
history of chemistry. 

Much of the science lore of the Arabs arose from 
their extensive trade, and in the practice of medi- 
cine. They introduced sugar-cane into Europe, im- 
proved the methods of manufacturing paper, discov- 
ered a method of obtaining alcohol, knew the uses 
of gypsum and of white arsenic, were expert in 
pharmacy and learned in materia medica. They are 
sometimes credited with introducing to the West the 
knowledge of the mariner's compass and of gun- 

Avicenna (980-1037), the Arab physician, not 
only wrote a large work on medicine (the Canon) 
based on the lore of Galen, which was used as a text- 
book for centuries in the universities of Europe, but 
wrote commentaries on all the works of Aristotle. 
"For AyejroesLyi 1 2fi-1 1 98V the Arab physician and 
philosopher, was reserved the title " The Commen- 
tator," due to his devotion to the works of the Greek 
biologist and philosopher. It was through the com- 


mentaries of Averroes that Aristotelian science be- 
came known in Europe during the Middle Ages. In 
his view Aristotle was the founder and perfecter of 
science ; yet he showed an independent knowledge of 
physics and chemistry, and wrote on astronomy and 
medicine as well as philosophy. He set forth the 
facts in reference to natural phenomena purely in 
the interests of the truth. He could not conceive of 
anything being created from nothing. At the same 
time he taught that God is the essence, the eternal 
cause, of progress. It is in humanity that intellect 
most clearly reveals itself, but there is a transcend- 
ent intellect beyond, union with which is the highest 
bliss of the individual soul. With the death of the 
Commentator the culture of liberal science among 
the Arabs came to an end, but his influence (and 
through him that of Aristotle) was perpetuated in all 
the western centers of education. 

The preservation of the ancient learning had not, 
however, depended solely on the Arabs. At the be- 
ginning of the sixth century, before the taking of 
Alexandria by the followers of Mohammed, St. Bene- 
dict had founded the monastery of Monte Cassino in 
Itafe Here was begun the copying of manuscripts, 
and the preparation of compendiums treating of 
grammar, dialectic, rhetoric, arithmetic, astronomy, 
music, and geometry. These were based on ancient 
Roman writings. Works like Pliny's Natural His- 
tory, the encyclopedia of the Middle Ages, had sur- 
vived all the wars by which Rome had been devas- 
tated. Learning, which in Rome's darkest days had 
found refuge in Britain and Ireland, returned book 
in hand. Charlemagne (800) called Alcuin from 


York to instruct princes and nobles at the Frankish 
court. At this same palace school half a century 
later the Irishman Scotus Erigena exhibited his learn- 
ing, wit, and logical acumen. In the tenth century 
Gerbert (Pope Sylvester II) learned mathematics 
at Arab schools in Spain. The translation of Arab 
works on science into the Latin language, freer in- 
tercourse of European peoples with the East through 
war and trade, economic prosperity, the liberation 
of serfs and the development of a well-to-do middle 
class, the voyages of Marco Polo to the Orient, the 
founding of universities, the encouragement of learn- 
ing by the Emperor Frederick II, the study of logic 
by the schoolmen, were all indicative of a new era in 
the history of scientific thought. 

The learnedj)ominican Albertus Magnus (1193- 
1280) was a careful student of Aristotle as well as 
of his Arabian commentators. In his many books on 
natural history he of course pays great deference to 
the Philosopher, but he is not devoid of original ob- 
servation. As the official visitor of his order he had 
traveled through the greater part of Germany on 
foot, and with a keen eye for natural phenomena was 
able to enrich botany and zoology by much accurate 
information. His intimacy with the details of natu- 
ral history made him suspected by the ignorant of 
the practice of magical arts. 

His pupil and disciple Thomas Aquinas (1227- 
1274) was the philosopher and recognized champion 
of the Christian Church. Li 1879 Pope Leo XIII, 
while proclaiming that every wise~saymg^ every use- 
ful discovery, by whomsoever it may be wrought, 
should be welcomed with a willing and grateful 


afterwards constructed ; he advocated basing natural 
science on experience and careful observation rather 
than on a process of reasoning. Roger Bacon's writ- 
ings are characterized by a philosophical breadth of 
view. To his mind the earth is only an insignificant 
dot in the center of the vast heavens. 

In the centuries that followed the death of Bacon 
the relation of this planet to the heavenly bodies was 
made an object of study by a succession of scientists 
who like him were versed in the achievements of pre- 
ceding ages. Peurbach (1423-1461), author of New 
TJieories of the Planets, developed the trigonometry 
of the Arabians, but died before fulfilling his plan 
to give Europe an epitome of the astronomy of 
Ptolemy. His pupil, Regiomontanus, however, more 
than made good the intentions of his master. The 
work of Peurbach had as commentator the first 
teacher in astronomy of Copernicus (1473-1543). 
Later ^IlapejUUj5jjpent nine years in Italy, study- 
ing at the universities and acquainting himself with 
Ptolemaic and other ancient views concerning the 
motions of the planets. He came to see that the ap- 
parent revolution of the heavenly bodies about the 
earth from east to west is really owing to the revolu- 
tion of the earth on its axis from west to east. This 
view was so contrary to prevailing beliefs that Co- 
pernicus refused to publish his theory for thirty-six 
years. A copy of his book, teaching that our earth is 
not the center of the universe, was brought to him on 
his deathbed, but he never opened it. 

Momentous as was this discovery, setting aside the 
geocentric system which had held captive the best 
minds for fourteen slow centuries and substituting the 


heliocentric, it was but a link in the chain of suc- 
cesses in astronomy to which Tycho Brahe, Kepler, 
Galileo, Newton, and their followers contributed. 


The Catholic Encyclopedia. 

J. L. E. Dreyer, History of the Planetary Systems. 
Encyclopaedia Britannica. Arabian Philosophy; Roger Bacon. 
W. J. Townsend, The Great Schoolmen of the Middle Ages. 
R. B. Vaughan, St. Thomas of Aquin; his Life and Labours. 
Andrew D. White, A History of the Warfare of Science with Theol- 
ogy in Christendom. 




THE preceding chapter has shown that there is a 
continuity in the development of single sciences. The 
astronomy, or the chemistry, or the mathematics, 
of one period depends so directly on the respective 
science of the foregoing period, that one feels justi- 
fied in using the term " growth," or " evolution," to 
describe their progress. Now a vital relationship can 
be observed not only among different stages of the 
same science, but also among the different sciences. 
Physics, astronomy, and chemistry have much in 
common ; geometry, trigonometry, arithmetic, and 
algebra are called " branches " of mathematics ; zo- 
ology and botany are biological sciences, as having 
to do with living species. In the century following 
the death of Copernicus, two great scientists, Bacon 
and Descartes, compared all knowledge to a tree, 
of which the separate sciences are branches. They 
thought of all knowledge as a living organism with 
an interconnection or continuity of parts, and a ca- 
pability of growth. 

By the beginning of the seventeenth century the 
sciences were so considerable that in the interest of 
further progress a comprehensive view of the tree 
of knowledge, a survey of the field of learning, was 
needed. The task of making this survey was under- 
taken by Francis Bacon, Lord Verulam (1561-1626). 


His classification of human knowledge was cele- 
brated, and very influential in the progress of sci- 
ence. He kept one clear purpose in view, namely, 
the control of nature by man. He wished to take 
stock of what had already been accomplished, to sup- 
ply deficiencies, and to enlarge the bounds of human 
empire. He was acutely conscious that this was an 
enterprise too great for any one man, and he used his 
utmost endeavors to induce James I to become the 
patron of the plan. His project admits of very simple 
statement now ; he wished to edit an encyclopedia, 
but feared that it might prove impossible without co- 
operation and without state support. He felt capable 
of furnishing the plans for the building, but thought 
it a hardship that he was compelled to serve both as 
architect and laborer. The worthiness of these plans 
was attested in the middle of the eighteenth century, 
when the great French Encyclopaedia was projected by 
Diderot and D'Alembert. The former, its chief edi- 
tor and contributor, wrote in the Prospectus : " If 
we come out successful from this vast undertaking, 
we shall owe it mainly to Chancellor Bacon, who 
sketched the plan of a universal dictionary of sciences 
and arts at a time when there were not, so to speak, 
either arts or sciences. This extraordinary genius, 
when it was impossible to write a history of what men 
knew, wrote one of what they had to learn." 

Bacon, as we shall amply see, was a firm believer 
in the study of the arts and occupations, and at the 
same time retained his devotion to principles and ab- 
stract thought. He knew that philosophy could aid 
the arts that supply daily needs ; also that the arts 
and occupations enriched the field of philosophy, 


and that the basis of our generalizations must be 
the universe of things knowable. " For," he writes, 
" if men judge that learning should be referred to 
use and action, they judge well ; but it is easy in this 
to fall into the error pointed out in the ancient fable ; 
in which the other parts of the body found fault with 
the stomach, because it neither performed the office 
of motion as the limbs do, nor of sense, as the head 
does ; but yet notwithstanding it is the stomach which 
digests and distributes the aliment to all the rest. So 
that if any man think that philosophy and universal- 
ity are idle and unprofitable studies, he does not con- 
sider that all arts and professions are from thence 
supplied with sap and strength." For Bacon, as for 
Descartes, natural philosophy was the trunk of the 
tree of knowledge. 

On the other hand, he looked to the arts, crafts, and 
occupations as a source of scientific principles. In his 
survey of learning he found some records of agri- 
culture and likewise of many mechanical arts. Some 
think them a kind of dishonor. " But if my judgment 
be of any weight, the use of History Mechanical is, 
of all others, the most radical and fundamental 
towards natural philosophy." When the different 
arts are known, the senses will furnish sufficient 
concrete material for the information of the under- 
standing. The record of the arts is of most use be- 
cause it exhibits things in motion, and leads more 
directly to practice. " Upon this history, therefore, 
mechanical and illiberal as it may seem (all fineness 
and daintiness set aside), the greatest diligence must 
be bestowed." " Again, among the particular arts 
those are to be preferred which exhibit, alter, and pre- 

Philosophia prima, or sapience 






















Civil Philosophy 

(Standards of 

right in :) 

of Humanity 






Medicine, Athletics, etc. 





(Material and Second- 
ary Causes) 

(Form and Final 


Purified Magic 






Natural Theology, Nature of Angels and Spirits 




C J 


Narrative, or Heroical 
Parabolic (Fables) 


(Civil History proper) 

Perfect History 




(Control by Man) 


(Nomic Law) 





Astronomical Physics 
Physical Geography 
Physics of Matter 
Organic Species 

Knowledge Classified (Hugo of St. Victor, d. 1141). 



Natural Philosophy 



Music (study of harmony) 




Ethics, or individual morality 
Economics, or family morality 
Politics, or civics 


Weaving, spinning, sewing ; work in wool, flax, etc. 

Equipment arms, ships ; work in stone, wood, metal 



Hunting, fishing, foods 


Theatricals drama, music, athletics, etc. 




pare natural bodies and materials of things as agri- 
culture, cooking, chemistry, dyeing ; the manufacture 
of glass, enamel, sugar, gunpowder, artificial fires, 
paper and the like." Weaving, carpentry, architec- 
ture, manufacture of mills, clocks, etc. follow. The 
purpose is not solely to bring the arts to perfection, 
but all mechanical experiments should be as streams 
flowing from all sides into the sea of philosophy. 

Shortly after James I came to the throne in 1603, 
Bacon published his Advancement of Learning. He 
continued in other writings, however, to develop the 
organization of knowledge, and in 1623 summed up 
his plan in the De Aug mentis Scientiarum. 

A recent writer (Pearson, 1900) has attempted 
to summarize Bacon's classification of the different 
branches of learning. When one compares this sum- 
mary with an outline of the classification of knowl- 
edge made by the French monk, Hugo of St. Victor, 
who stands midway between Isidore of Seville (570- 
636) and Bacon, some points of resemblance are of 
course obvious. Moreover, Hugo, like Bacon, insisted 
on the importance of not being narrowly utilitarian. 
Men, he says, are often accustomed to value knowl- 
edge not on its own account but for what it yields. 
Thus it is with the arts of husbandry, weaving, paint- 
ing, and the like, where skill is considered absolutely 
vain, unless it results in some useful product. If, 
however, we judged after this fashion of God's wis- 
dom, then, no doubt, the creation would be preferred 
to the Creator. But wisdom is life, and the love of 
wisdom is the joy of life (fdidtaswtci). 

Nevertheless, when we compare these classifications 
diligently, we find very marked differences between 


Bacon's views and the medieval. The weakest part 
of Hugo's classification is that which deals with 
natural philosophy. Physica, he says, undertakes the 
investigation of the causes of things in their effects, 
and of effects in their causes. It deals with the ex- 
planation of earthquakes, tides, the virtues of plants, 
the fierce instincts of wild animals, every species of 
stone, shrub, and reptile. When we turn to his spe- 
cial work, however, on this branch of knowledge, 
Concerning Beasts and Other Things, we find no 
attempt to subdivide the field of physica, but a se- 
ries of details in botany, geology, zoology, and human 
anatomy, mostly arranged in dictionary form. 

When we refer to Bacon's classification we find 
that Physics corresponds to Hugo's Physica. It 
studies natural phenomena in relation to their ma- 
terial causes. For this study, Natural History, ac- 
cording to Bacon, supplies the facts. Let us glance, 
then, at his work on natural history, and see how 
far he had advanced from the medieval toward the 
modern conception of the sciences. 

For purposes of scientific study he divided the 
phenomena of the universe into (1) Celestial phe- 
nomena ; (2) Atmosphere ; (3) Globe ; (4) Substance 
of earth, air, fire, water; (5) Genera, species, etc. 
Great scope is given to the natural history of man. 
The arts are classified as nature modified by man. 
History means, of course, descriptive science. With 
these histories enumerated by Bacon may be com- 
pared the following list of sciences : physics, chem- 
istry, astronomy, geology ; botany, zoology, anatomy ; 
psychology, sociology ; logic, mathematics ; medicine, 
technology ; pedagogy, jurisprudence, economics. 


Bacon's Catalogue of Particular Histories by Titles 


1. History of the Heavenly Bodies; or Astronomical 

2. History of the Configuration of the Heavens and the 
parts thereof towards the Earth and the parts thereof; 
or Cosmographical History. 

3. History of Comets. 

4. History of Fiery Meteors. 

5. History of Lightnings, Thunderbolts, Thunders, and 

6. History of Winds and Sudden Blasts and Undulations 
of the Air. 

7. History of Rainbows. 

8. History of Clouds, as they are seen above. 

9. History of the Blue Expanse, of Twilight, of Mock- 
Suns, Mock-Moons, Haloes, various colours of the 
Sun; and of every variety in the aspect of the heav- 
ens caused by the medium. 

10. History of Showers, Ordinary, Stormy, and Prodi- 
gious; also of Waterspouts (as they are called); and 
the like. 

11. History of Hail, Snow, Frost, Hoar-frost, Fog, Dew, 
and the like. 

12. History of all other things that fall or descend from 
above, and that are generated in the upper region. 

13. History of Sounds in the upper region (if there be 
any) , besides Thunder. 

14. History of Air as a whole, or in the Configuration of 
the World. 

15. History of the Seasons or Temperatures of the Year, 
as well according to the variations of Regions as ac- 
cording to accidents of Times and Periods of Years; 
of Floods, Heats, Droughts, and the like. 

16. History of Earth and Sea; of the Shape and Compass 
of them, and their Configurations compared with each 
other; and of their broadening or narrowing; of Islands 
in the Sea; of Gulfs of the Sea, and Salt Lakes within 
the Land; Isthmuses and Promontories. 


17. History of the Motions (if any be) of the Globe of 
Earth and Sea; and of the Experiments from which 
such motions may be collected. 

18. History of the greater motions and Perturbations in 
Earth and Sea; Earthquakes, Tremblings and Yawn- 
ings of the Earth, Islands newly appearing; Float- 
ing Islands; Breakings off of Land by entrance of 
the Sea, Encroachments and Inundations and con- 
trariwise Recessions of the Sea; Eruptions of Fire 
from the Earth; Sudden Eruptions of Waters from 
the Earth; and the like. 

19. Natural History of Geography; of Mountains, Vallies, 
Woods, Plains, Sands, Marshes, Lakes, Rivers, Tor- 
rents, Springs, and every variety of their course, and 
the like; leaving apart Nations, Provinces, Cities, 
and such like matters pertaining to Civil life. 

20. History of Ebbs and Flows of the Sea; Currents, Un- 
dulations, and other Motions of the Sea. 

21. History of other Accidents of the Sea; its Saltness, its 
various Colours, its Depth; also of Rocks, Mountains, 
and Vallies under the Sea, and the like. 

Next come Histories of the Greater Masses 

22. History of Flame and of things Ignited. 

23. History of Air, in Substance, not in the Configuration 
of the World. 

24. History of Water, in Substance, not in the Configu- 
ration of the World. 

25. History of the Earth and the diversity thereof, in 
Substance, not in the Configuration of the World. 

Next come Histories of Species 

26. History of perfect Metals, Gold, Silver; and of the 
Mines, Veins, Marcasites of the same; also of the 
Working in the Mines. 

27. History of Quicksilver. 

28. History of Fossils; as Vitriol, Sulphur, etc. 

29. History of Gems; as the Diamond, the Ruby, etc. 


30. History of Stones; as Marble, Touchstone, Flint, etc. 

31. History of the Magnet. 

32. History of Miscellaneous Bodies, which are neither 
entirely Fossil nor Vegetable; as Salts, Amber, Am- 
bergris, etc. 

33. Chemical History of Metals and Minerals. 

34. History of Plants, Trees, Shrubs, Herbs; and of their 
parts, Roots, Stalks, Wood, Leaves, Flowers, Fruits, 
Seeds, Gums, etc. 

35. Chemical History of Vegetables. 

36. History of Fishes, and the Parts and Generation of 

37. History of Birds, and the Parts and Generation of 

38. History of Quadrupeds, and the Parts and Generation 
of them. 

39. History of Serpents, Worms, Flies, and other insects; 
and of the Parts and Generation of them. 

40. Chemical History of the things which are taken by 

Next come Histories of Man 

41. History of the Figure and External Limbs of man, his 
Stature, Frame, Countenance, and Features; and of 
the variety of the same according to Races and 
Climates, or other smaller differences. 

42. Physiognomical History of the same. 

43. Anatomical History, or of the Internal Members of 
Man; and of the variety of them, as it is found in the 
Natural Frame and Structure, and not merely as 
regards Diseases and Accidents out of the course of 

44. History of the parts of Uniform Structure in Man; 
as Flesh, Bones, Membranes, etc. 

45. History of Humours in Man; Blood, Bile, Seed, etc. 

46. History of Excrements; Spittle, Urine, Sweats, Stools, 
Hair of the Head, Hairs of the Body, Whitlows, Nails, 
and the like. 

47. History of Faculties; Attraction, Digestion, Reten- 


tion, Expulsion, Sanguification, Assimilation of Ali- 
ment into the members, conversion of Blood and 
Flower of Blood into Spirit, etc. 

48. History of Natural and Involuntary Motions; as Mo- 
tion of the Heart, the Pulses, Sneezing, Lungs, 
Erection, etc. 

49. History of Motions partly Natural and Partly Violent; 
as of Respiration, Cough, Urine, Stool, etc. 

50. History of Voluntary Motions; as of the Instruments 
of Articulation of Words; Motions of the Eyes. 
Tongue, Jaws, Hands, Fingers; of Swallowing, etc. 

51. History of Sleep and Dreams. 

52. History of different habits of Body - Fat, Lean; 
of the Complexions (as they call them), etc. 

53. History of the Generation of Man. 

54. History of Conception, Vivification, Gestation in the 
Womb, Birth, etc. 

55. History of the Food of Man; and of all things Eatable 
and Drinkable; and of all Diet; and of the variety 
of the same according to nations and smaller differ- 

56. History of the Growth and Increase of the Body, in 
the whole and in its parts. 

57. History of the Course of Age; Infancy, Boyhood, 
Youth, Old Age; of Length and Shortness of Life, and 
the like, according to nations and lesser differences. 

58. History of Life and Death. 

59. History Medicinal of Diseases, and of the Symptoms 
and Signs of them. 

60. History Medicinal of the Treatment and Remedies 
and Cures of Diseases. 

61. History Medicinal of those things which preserve the 
Body and the Health. 

62. History Medicinal of those things which relate to the 
Form and Comeliness of the Body. 

63. History Medicinal of those things which alter the 
Body, and pertain to Alterative Regimen. 

64. History of Drugs. 


65. History of Surgery. 

66. Chemical History of Medicines. 

67. History of Vision, and of things Visible. 

68. History of Painting, Sculpture, Modelling, etc. 

69. History of Hearing and Sound. 

70. History of Music. 

71. History of Smell and Smells. 

72. History of Taste and Tastes. 

73. History of Touch, and the objects of Touch. 

74. History of Venus, as a species of Touch. 

75. History of Bodily Pains, as species of Touch. 

76. History of Pleasure and Pain in general. 

77. History of the Affections; as Anger, Love, Shame, 

78. History of the Intellectual Faculties; Reflexion, 
Imagination, Discourse, Memory, etc. 

79. History of Natural Divinations. 

80. History of Diagnostics, or Secret Natural Judgements. 

81. History of Cookery, and of the arts thereto belonging, 
as of the Butcher, Poulterer, etc. 

82. History of Baking, and the Making of Bread, and the 
arts thereto belonging, as of the Miller, etc. 

83. History of Wine. 

84. History of the Cellar and of different kinds of Drink. 

85. History of Sweetmeats and Confections. 

86. History of Honey. 

87. History of Sugar. 

88. History of the Dairy. 

89. History of Baths and Ointments. 

90. Miscellaneous History concerning the care of the 
body as of Barbers, Perfumers, etc. 

91. History of the working of Gold, and the arts thereto 

92. History of the manufactures of Wool, and the arts 
thereto belonging. 

93. History of the manufactures of Silk, and the arts 
thereto belonging. 

94. History of the manufactures of Flax, Hemp, Cotton, 


Hair, and other kinds of Thread, and the arts 
thereto belonging. 

95. History of manufactures of Feathers. 

96. History of Weaving, and the arts thereto belonging. 

97. History of Dyeing. 

98. History of Leather-making, Tanning, and the arts 
thereto belonging. 

99. History of Ticking and Feathers. 

100. History of working in Iron. 

101. History of Stone-cutting. 

102. History of the making of Bricks and Tiles. 

103. History of Pottery. 

104. History of Cements, etc. 

105. History of working in Wood. 

106. History of working in Lead. 

107. History of Glass and all vitreous substances, and of 

108. History of Architecture generally. 

109. History of Waggons, Chariots, Litters, etc. 

110. History of Printing, of Books, of Writing, of Sealing; 
of Ink, Pen, Paper, Parchment, etc. 

111. History of Wax. 

112. History of Basket-making. 

113. History of Mat-making, and of manufactures of 
Straw, Rushes, and the like. 

114. History of Washing, Scouring, etc. 

115. History of Agriculture, Pasturage, Culture of Woods, 

116. History of Gardening. 

117. History of Fishing. 

118. History of Hunting and Fowling. 

119. History of the Art of War, and of the arts thereto 
belonging, as Armoury, Bow-making, Arrow-making, 
Musketry, Ordnance, Cross-bows, Machines, etc. 

120. History of the Art of Navigation, and of the crafts 
and arts thereto belonging. 

121. History of Athletics and Human Exercises of all kinds. 

122. History of Horsemanship. 

123. History of Games of all kinds. 

124. History of Jugglers and Mountebanks. 


125. Miscellaneous History of various Artificial Materials, 
Enamel, Porcelain, various cements, etc. 

126. History of Salts. 

127. Miscellaneous History of various Machines and Mo- 

128. Miscellaneous History of Common Experiments 
which have not grown into an Art. 

Histories must also be written of Pure Mathematics ; though 
they are rather observations than experiments 

129. History of the Natures and Powers of Numbers. 

130. History of the Natures and Powers of Figures. 

The fragment containing this catalogue (^Parasceve 
Day of Preparation) was added to Bacon's work 
on method, The New. Logic (Novum Organum), 
1620. Besides completing his survey and classifica- 
tion of the sciences (De, Augmentis Scientiarum), 
1623, he published a few separate writings on topics 
in the catalogue Winds, Life and Death, Tides, 
etc. In 1627, a year after his death, appeared his 
much misunderstood work, Sylva Sylvarum. He had 
found that the Latin word sylva meant stuff or raw 
material, as well as a wood, and called this final 
work Sylva Sylvarum, which I would translate, 
"Jungle of Raw Material." He himself referred to 
it as "an undigested heap of particulars" ; yet he was 
willing it should be published because "he preferred 
the good of men to anything that might have relation 
to himself." In it, following his catalogue, he fulfilled 
the promise made in 1620, of putting nature and the 
arts to question. Some of the problems suggested for 
investigation are : congealing of air, turning air into 
water, the secret nature of flame, motion of gravity, 


production of cold, nourishing of young creatures in 
the egg or womb, prolongation of life, the media of 
sound, infectious diseases, accelerating and prevent- 
ing putrefaction, accelerating and staying growth, 
producing fruit without core or seed, production of 
composts and helps for ground, flying in the air. 

In the New Atlantis, a work of imagination, Bacon 
had represented as already achieved for mankind 
some of the benefits he wished for : artificial metals, 
various cements, excellent dyes, animals for vivisec- 
tion and medical experiment, instruments which gen- 
erate heat solely by motion, artificial precious stones, 
conveyance of sound for great distances and in tor- 
tuous lines, new explosives. " We imitate," says the 
guide in the Utopian land, " also flights of birds ; we 
have some degree of flying in the air ; we have ships 
and boats for going under water." Bacon believed in 
honoring the great discoverers and inventors, and 
advocated maintaining a calendar of inventions. 

He was a fertile and stimulating thinker, and much 
of his great influence arose from the comprehensive- 
ness that led to his celebrated classification of the 



Bacon's Philosophical Works, vol. iv, Parasceve, edited by R. L. 

Ellis, J. Spedding, and D. D. Heath. 
Karl Pearson, Grammar of Science. 
J. A. Thomson, Introduction to Science. 




THE previous chapter lias given some indication of 
the range of the material which was demanding scien- 
tific investigation at the end of the sixteenth and the 
beginning of the seventeenth century. The same 
period witnessed a conscious development of the 
method, or methods, of investigation. As we have 
seen, Bacon wrote in 1620 a considerable work, The 
New Logic (Novum Organurti), so called to dis- 
tinguish it from the traditional deductive logic. It 
aimed to furnish the organ or instrument, to indi- 
cate the correct mental procedure, to be employed in 
the discovery of natural law. Some seventeen years 
later, the illustrious Frenchman Rene Descartes 
(1596-1650) published his Discourse on the Method 
of rightly conducting the Reason and seeking Truth 
in the Sciences. Both of these philosophers illustrated 
by their own investigations the efficiency of the 
methods which they advocated. 

Before 1620, however, the experimental method 
had already yielded brilliant results in the hands of 
other scientists. We pass over Leonardo da Vinci 
and many others in Italy and elsewhere, whose names 
should be mentioned if we were tracing this method 
[j toitsorigin. By 1600 William Gilbert (1540-1603), 
physician to Queen Elizabeth, before whom, as a 
picture in his birthplace illustrates, he was called to 


demonstrate his discoveries, had published his work 
on the Magnet, the outcome of about eighteen years 
of critical research. He may be considered the founder 
of electrical science. Galileo, who discovered the 
fundamental principles of dynamics and thus laid the 
basis of modern physical science, although he did not 
publish his most important work till 1638, had even 
before the close of the sixteenth century prepared 
the way for the announcement of his principles by 
years of strict experiment. By the year 1616, William 
Harvey (15 7 8-1 6 5 7), physician at the court of James 
I, and, later, of Charles I, had, as the first modern 
experimental physiologist, gained important results 
through his study of the circulation of the blood. 

It is not without significance that both Gilbert and 
Harvey had spent years in Italy, where, as we have 
implied, the experimental method of scientific re- 
search was early developed. Harvey was at Padua 
(1598-1602) within the time of Galileo's popular 
professoriate, and may well have been inspired by 
the physicist to explain on dynamical principles the 
flow of blood through arteries and veins. This con- 
jecture is the more probable, since Galileo, like Har- 
vey and Gilbert, had been trained in the study of 
medicine. Bacon in turn had in his youth learned 
something of the experimental method on the Conti- 
nent of Europe, and, later, was well aware of the 
studies of Gilbert and Galileo, as well as of Harvey, 
who was indeed his personal physician. 

Although these facts seem to indicate that method 
may be transmitted in a nation or a profession, or 
through personal association, there still remains some 
doubt as to whether anything so intimate as the 


mental procedure involved in invention and in the 
discovery of truth can be successfully imparted by 
instruction. The individuality of the man of genius 
engaged in investigation must remain a factor diffi- 
cult to analyze. Bacon, whose purpose was to hasten 
man's empire over nature through increasing the 
number of inventions and discoveries, recognized 
that the method he illustrated is not the sole method 
of scientific investigation. In fact, he definitely states 
that the method set forth in the Novum Organum 
is not original, or perfect, or indispensable. He was 
aware that his method tended to the ignoring of 
genius and to the putting of intelligences on one level. 
He knew that, although it is desirable for the inves- 
tigator to free his mind from prepossessions, and to 
avoid premature generalizations, interpretation is the 
true and natural work of the mind when free from 
impediments, and that the conjecture of the man of 
genius must at times anticipate the slow process of 
painful induction. (As we shall see in the nineteenth 
chapter, the psychology of to-day does not know 
enough about the workings of the mind to prescribe 
a fixed mental attitude for the investigator. Never- 
theless, Bacon was not wrong in pointing out the 
virtues of a method which he and many others turned 
to good account. Let us first glance, however, at the 
activities of those scientists who preceded Bacon in 
the employment of the experimental method. 

Gilbert relied, in his investigations, on oft-repeated 
and verifiable experiments, as can be seen from his 
work De Magnete. He directs the experimenter, for 
example, to take a piece of loadstone of convenient 
size and turn it on a lathe to the form of a ball. It 


then may be called a terrella, or earthkin. Place on it 
a piece of iron wire. The ends of the wire move round 
its middle point and suddenly come to a standstill. 
Mark with chalk the line along which the wire lies 
still and sticks. Then move the wire to other spots 
on the terrella and repeat your procedure. The lines 
thus marked, if produced, will form meridians, all 
coming together at the poles. Again, place the mag- 
net in a wooden vessel, and then set the vessel afloat 
in a tub or cistern of still water. The north pole of the 
stone will seek approximately the direction of the 
south pole of the earth, etc. It was on the basis of 
scores of experiments of this sort, carried on from 
about 1582 till 1600, that Gilbert felt justified in 
concluding that the terrestrial globe is a magnet. 
This theory has since that time been abundantly 
confirmed by navigators. The full title of his book 
is Concerning the Magnet and Magnetic Bodies, 
and concerning the Great Magnet the Earth: A 
New Natural History {Physiologia) demonstrated 
by many Arguments and Experiments. It does not 
detract from the credit of Gilbert's result to state 
that his initial purpose was not to discover the nature 
of magnetism or electricity, but to determine the true 
substance of the earth, the innermost constitution of 

. i 

the globe. He was fully conscious of his own method 
and speaks with scorn of certain writers who, having 
made no magnetical experiments, constructed ratio- 
cinations on the basis of mere opinions and old- 
womanishly dreamed the things that were not. 

Galileo (1564-1642) even as a child displayed 
something of the inventor's ingenuity, and when he 
was nineteen, shortly after the beginning of Gilbert's 


experiments, his keen perception for the phenomena of 
motion led to his making a discovery of great scien- 
tific moment. He observed a lamp swinging by a long 
chain in the cathedral of his native city of Pisa, and 
noticed that, no matter how much the range of the 
oscillations might vary, their times were constant. 
He verified his first impressions by counting his 
pulse, the only available timepiece. Later he invented 
simple pendulum devices for timing the pulse of pa- 
tients, and even made some advances in applying his 
discovery in the construction of pendulum clocks. 

In 1589 he was appointed professor of mathemat- 
ics in the University of Pisa, and within a year 
or two established through experiment the founda- 
tions of the science of dynamics. As early as 1590 
he put on record, in a Latin treatise Concerning 
Motion (De Motu), his dissent from the theories of 
Aristotle in reference to moving bodies, confuting 
the Philosopher both by reason and ocular demon- 
stration. Aristotle had held that two moving bodies 
of the same sort and in the same medium have 
b velocities in proportion to their 

weights. If a moving body, whose 
weight is represented by 5, be car- 
ried through the line c e which 
is divided in the point d, if, also, 
the moving body is divided accord- 
ing to the same proportion as line 
c e is in the point d, it is manifest 
that in the time taken to carry the 
whole body through c e, the part 
will be moved through c d. Gali- 
leo said that it is as clear as day- 


light that this view is ridiculous, for who would be- 
lieve that when two lead spheres are dropped from a 
great height, the one being a hundred times heavier 
than the other, if the larger took an hour to reach 
the earth, the smaller would take a hundred hours? 
Or, that if from a high tower two stones, one twice 
the weight of the other, should be pushed out at the 
same moment, the larger would strike the ground 
while the smaller was still midway? His biography 
tells that Galileo in the presence of professors and 
students dropped bodies of different weights from 
the height of the Leaning Tower of Pisa to demon- 
strate the truth of his views. If allowance be made 
for the friction of the air, all bodies fall from the 
same height in equal times : the final velocities are 
proportional to the times ; the spaces passed through 
are proportional to the squares of the times. The 
experimental basis of the last two statements was 
furnished by means of an inclined plane, down a 
smooth groove in which a bronze ball was allowed to 
pass, the time being ascertained by means of an 
improvised water-clock. 

Galileo's mature views on dynamics received ex- 
pression in a work published in 1638, Mathematical 
Discourses and Demonstrations concerning Two 
New Sciences relating to Mechanics and Local 
Movements. It treats of cohesion and resistance to 
fracture (strength of materials), and uniform, ac- 
celerated, and projectile motion (dynamics). The dis- 
cussion is in conversation form. The opening sentence 
shows Galileo's tendency to base theory on the em- 
pirical. It might be freely translated thus : " Large 
scope for intellectual speculation, I should think, 


would be afforded, gentlemen, by frequent visits to 
your famous Venetian Dockyard (jar senate), espe- 
cially that part where mechanics are in demand ; 
seeing that there every sort of instrument and ma- 
chine is put to use by numbers of workmen, among 
whom, taught both by tradition and their own ob- 
servation, there must be some very skillful and also 
able to talk." The view of the shipbuilders, that a 
large galley before being set afloat is in greater dan- 
ger of breaking under its own weight than a small 
galley, is the starting-point of this most important 
of Galileo's contributions to science. 

Vesalius (1514-1564) had in his work on the 
structure of the human body (De Humani Corporis 
Fabrica, 1543) shaken the authority of Galen's 
anatomy ; it remained for Harvey on the basis of 
the new anatomy to improve upon the Greek physi- 
cian's experimental physiology. Harvey professed to 
learn and teach anatomy, not from books, but from 
dissections, not from the dogmas of the philosophers, 
but from the fabric of nature. 

There have come down to us notes of his lectures 
on anatomy delivered first in 1616. A brief extract 
will show that even at that date he had already for- 
mulated a theory of the circulation of the blood : 

"Wf 1 By the structure of the heart it appears 
that the blood is continually transfused through the 
lungs to the aorta as by the two clacks of a water- 
ram for raising water. 

" It is shown by ligature that there is continuous 
motion of the blood from arteries to veins. 

1 This is Harvey's monogram, which he used in his notes to 
mark any original observation. 


" Whence A it is demonstrated that there is a con- 
tinuous motion of the blood in a circle, effected by 
the beat of the heart." 

It was not till 1628 that Harvey published his 
Anatomical Disquisition on the Motion of the Heart 
and Blood in Animals. It gives the experimental 
basis of his conclusions. If a live snake be laid open, 
the heart will be seen pulsating and propelling its 
contents. Compress the large vein entering the heart, 
and the part intervening between the point of constric- 
tion and the heart becomes empty and the organ pales 
and shrinks. Remove the pressure, and the size and 
color of the heart are restored. Now compress the 
artery leading from the organ, and the part between 
the heart and the point of pressure, and the heart 
itself, become distended and take on a deep purple 
color. The course of the blood is evidently from the 
vena cava through the heart to the aorta. Harvey in 
his investigations made use of many species of ani- 
mals at least eighty-seven. 

It was believed by some, before Harvey's demon- 
strations, that the arteries were hollow pipes carry- 
ing air from the lungs throughout the body, although 
Galen had shown by cutting a dog's trachea, inflat- 
ing the lungs and tying the trachea, that the lungs 
were in an enclosing sack which retained the air. 
Harvey, following Galen, held that the pulmonary 
artery, carrying blood to the lungs from the right 
side of the heart, and the pulmonary veins, carrying 
blood from the lungs to the left side of the heart, in- 
tercommunicate in the hidden porosities of the lungs 
and through minute inosculations. 

In man the vena cava carries the blood to the right 


side of the heart, the pulmonary artery inosculates 
with the pulmonary veins, which convey it to the left 
side of the heart. This muscular pump drives it into 
the aorta. It still remains to be shown that in the 
limbs the blood passes from the arteries to the veins. 
Bandage the arm so tightly that no pulse is felt at 
the wrist. The hand appears at first natural, and 
then grows cold. Loose the bandage sufficiently to 
restore the pulse. The hand and forearm become 
suffused and swollen. In the first place the supply 
of blood from the deep-lying arteries is cut off. In 
the second case the blood returning by the superficial 
veins is dammed back. In the limbs as in the lungs 
the blood passes from artery to vein by anastomoses 
and porosities. All these arteries have their source 
in the aorta ; all these veins pour their stream ulti- 
mately into the vena cava. The veins have valves, 
which prevent the blood flowing except toward the 
heart. Again, the veins and arteries form a connected 
system ; for through either a vein or an artery all 
the blood may be drained off. The arguments by 
which Harvey supported his view were various. The 
opening clause of his first chapter, " When I first 
gave my mind to vivisection as a means of discover- 
ing the motions and uses of the heart," throws a 
strong light on his special method of experimental 

Bacon, stimulated by what he called philanthropic^, 
always aimed, as we have seen, to establish man's 
control over nature. But all power of a high order 
depends on an understanding of the essential char- 
acter, or law, of heat, light, sound, gravity, and the 
like. Nothing short of a knowledge of the underly- 


ing nature of phenomena can give science advantage 
over chance in hitting upon useful discoveries and 
inventions. It is, therefore, natural to find him ap- 
plying his method of induction his special method 
of true induction to the investigation of heat. 

In the first place, let there be mustered, without 
premature speculation, all the instances in which 
heat is manifested flame, lightning, sun's rays, 
quicklime sprinkled with water, damp hay, animal 
heat, hot liquids, bodies subjected to friction. Add 
to these, instances in which heat seems to be absent, 
as moon's rays, sun's rays on mountains, oblique rays 
in the polar circle. Try the experiment of concen- 
trating on a thermoscope, by means of a burning- 
glass, the moon's rays. Try with the burning-glass 
to concentrate heat from hot iron, from common 
flame, from boiling water. Try a concave glass with 
the sun's rays to see whether a diminution of heat 
results. Then make record of other instances, in 
which heat is found in varying degrees. For exam- 
ple, an anvil grows hot under the hammer. A thin 
plate of metal under continuous blows might grow 
red like ignited iron. Let this be tried as an experi- 

After the presentation of these instances induction 
itself must be set to work to find out what factor is 
ever present in the positive instances, what factor 
is ever wanting in the negative instances, what fac- 
tor always varies in the instances which show varia- 
tion. According to Bacon it is in the process of 
exclusion that the foundations of true induction are 
laid. We can be certain, for example, that the 
essential nature of heat does not consist in light and 


brightness, since it is present in boiling water and 
absent in the moon's rays. 

The induction, however, is not complete till some- 
thing positive is established. At this point in the 
investigation it is permissible to venture an hypoth- 
esis in reference to the essential character of heat. 
From a survey of the instances, all and each, it ap- 
pears that the nature of which heat is a particular 
case is motion. This is suggested by flame, sim- 
mering liquids, the excitement of heat by motion, 
the extinction of fire by compression, etc. Motion is 
the genus of which heat is the species. Heat itself, 
its essence, is motion and nothing else. 

It remains to establish its specific differences. 
This accomplished, we arrive at the definition : Heat 
is a motion, expansive, restrained, and acting in its 
strife upon the smaller particles of bodies. Bacon, 
glancing toward the application of this discovery, 
adds: " If 'in any natural body you can excite a 
dilating or expanding motion, and can so repress 
this motion and turn it back upon itself, that the 
dilation shall not proceed equally, but have its way 
in one part and be counteracted in another, you will 
undoubtedly generate heat" The reader will recall 
that Bacon looked for the invention of instruments 
that would generate heat solely by motion. 

Descartes was a philosopher and mathematician. 
In his Discourse on Method and his Rules for the 
Direction of the Mind (1628) he laid emphasis on 
deduction rather than on induction. In the subor- 
dination of particulars to general principles he ex- 
perienced a satisfaction akin to the sense of beauty 
or the joy of artistic production. He speaks enthusi- 


astically of that pleasure which one feels in truth, 
and which in this world is about the only pure and 
unmixed happiness. 

At the same time he shared Bacon's distrust of 
the Aristotelian logic and maintained that ordinary 
dialectic is valueless for those who desire to investi- 
gate the truth of things. There is need of a method 
for finding out the truth. He compares himself to a 
smith forced to begin at the beginning by fashion- 
ing tools with which to work. 

In his method of discovery he determined to ac- 
cept nothing as true that he did not clearly recog- 
nize to be so. He stood against assumptions, and 
insisted on rigid proof. Trust only what is com- 
pletely known. Attain a certitude equal to that of 
arithmetic and geometry. This attitude of strict 
criticism is characteristic of the scientific mind. 

Again, Descartes was bent on analyzing each dif- 
ficulty in order to solve it ; to neglect no intermediate 
steps in the deduction, but to make the enumeration 
of details adequate and methodical. Preserve a cer- 
tain order ; do not attempt to jump from the ground 
to the gable, but rise gradually from what is simple 
and easily understood. 

Descartes' interest was not in the several branches 
of mathematics ; rather he wished to establish a uni- 
versal mathematics, a general science relating to 
order and measurement. He considered all physical 
nature, including the human body, as a mechanism, 
capable of explanation on mathematical principles. 
But his immediate interest lay in numerical relation- 
ships and geometrical proportions. 

Recognizing that the understanding was depend- 


ent on the other powers of the mind, Descartes 
resorted in his mathematical demonstrations to the 
use of lines, because he could find no method, as he 
says, more simple or more capable of appealing to 
the imagination and senses. He considered, how- 
ever, that in order to bear the relationships in mem- 
ory or to embrace several at once, it was essential to 
explain them by certain formula, the shorter the 
better. And for this purpose it was requisite to 
borrow all that was best in geometrical analysis and 
algebra, and to correct the errors of one by the other. 
Descartes was above all a mathematician, and as 
such he may be regarded as a forerunner of Newton 
and other scientists; at the same time he developed an 
exact scientific method, which he believed applicable 
to all departments of human thought. " Those long 
chains of reasoning," he says, " quite simple and 
easy, which geometers are wont to employ in the 
accomplishment of their most difficult demonstra- 
tions, led me to think that everything which might 
fall under the cognizance of the human mind might 
be connected together in the same manner, and that, 
provided only one should take care not to receive 
anything as true which was not so, and if one were 
always careful to preserve the order necessary for 
deducing one truth from another, there would be 
none so remote at which he might not at last arrive, 
or so concealed which he might not discover.'* 



Francis Bacon, Philosophical Works (Ellis and Spedding edi- 
tion), vol. iv, Novum Organum. 

J. J. Fahie, Galileo; His Life and Work. 

Galileo, Two New Sciences; translated by Henry Crew and 
Alphonse De Salvio. 

William Gilbert, On the Loadstone ; translated by P. F. Motte- 

William Harvey, An Anatomical Disquisition on the Motion of 
the Heart and Blood in Animals. 

T. H. Huxley, Method and Results. 

D'Arcy Power, William Harvey (in Masters of Medicine). 




CONSIDERING the value for clearness of thought of 
counting, measuring and weighing, it is not surpris- 
ing to find that in the seventeenth century, and even 
at the end of the sixteenth, the advance of the sciences 
was accompanied by increased exactness of measure- 
ment and by the invention of instruments of pre- 
cision. The improvement of the simple microscope, 
the invention of the compound microscope, of the 
telescope, the micrometer, the barometer, the thermo- 
scope, the thermometer, the pendulum clock, the 
improvement of the mural quadrant, sextant, spheres, 
astrolabes, belong to this period. 

Measuring is a sort of counting, and weighing a 
form of measuring. We may count disparate things 
whether like or unlike. When we measure or weigh 
we apply a standard and count the times that the unit 
cubit, pound, hour is found to repeat itself. We 
apply our measure to uniform extension, meting out 
the waters by fathoms or space by the sun's diameter, 
and even subject time to arbitrary divisions. The hu- 
man mind has been developed through contact with 
the multiplicity of physical objects, and we find it 
impossible to think clearly and scientifically about 
our environment without dividing, weighing, measur- 
ing, counting. 

In measuring time we cannot rely on our inward 


impressions ; we even criticize these impressions and 
speak of time as going slowly or quickly. We are 
compelled in the interests of accuracy to provide an 
objective standard in the clock, or the revolving 
earth, or some other measurable thing. Similarly 
with weight and heat ; we cannot rely on the subjec- 
tive impression, but must devise apparatus to record 
by a measurable movement the amount of the pres- 
sure or the degree of temperature. 

" God ordered all things by measure, number, and 
weight." The scientific mind does not rest satisfied 
till it is able to see phenomena in their number re- 
lationships. Scientific thought is in this sense Pythag- 
orean, that it inquires in reference to quantity and 

As implied in a previous chapter, number relations 
are not clearly grasped by primitive races. Many 
primitive languages have no words for numerals 
higher than five. That fact does not imply that these 
races do not know the difference between large and 
small numbers, but precision grows with civilization, 
with commercial pursuits, and other activities, such 
as the practice of medicine, to which the use of weights 
and measures is essential. Scientific accuracy is de- 
pendent on words and other means of numerical expres- 
sion. From the use of fingers and toes, a rude score 
or tally, knots on a string, or a simple abacus, the 
race advances to greater refinement of numerical 
expression and the employment of more and more 
accurate apparatus. 

One of the greatest contributors to this advance 
was the celebrated Danish astronomer, Tycho Brahe 
(1546-1601). Before 1597 he had completed his 


great mural quadrant at the observatory of Urani- 
borg. He called it with characteristic vanity the 
Tichonic quadrant. It consisted of a graduated arc 
of solid polished brass five inches broad, two inches 
thick, and with a radius of about six and three quar- 
ters feet. Each degree was divided into minutes, and 
each minute into six parts. Each of these parts was 
then subdivided into ten seconds, which were indi- 
cated by dots arranged in transverse oblique lines on 
the width of brass. 

The arc was attached in the observation room to 
a wall running exactly north, and so secured with 
screws (firmissimis cochleis) that no force could 
move it. With its concavity toward the southern sky 
it was closely comparable, though reverse, to the 
celestial meridian throughout its length from horizon 
to zenith. The south wall, above the point where the 
radii of the quadrant met, was pierced by a cylinder 
of gilded brass placed in a rectangular opening, which 
could be opened or closed from the outside. The ob- 
servation was made through one of two sights that 
were attached to the graduated arc and could be 
moved from point to point on it. In the sights were 
parallel slits, right, left, upper, lower. If the alti- 
tude and the transit through the meridian were to 
be taken at the same time the four directions were to 
be followed. It was the practice for the student mak- 
ing the observation to read off the number of degrees, 
minutes, etc., of the angle at which the altitude or 
transit was observed, so that it might be recorded by 
a second student. A third took the time from two 
clock dials when the observer gave the signal, and the 
exact moment of observation was also recorded by 





student number two. The clocks recorded minutes 
and the smaller divisions of time ; great care, however, 
was required to obtain good results from them. There 
were four clocks in the observatory, of which the 
largest had three wheels, one wheel of pure solid brass 
having twelve hundred teeth and a diameter of two 

Lest any space on the wall should lie empty a num- 
ber of paintings were added : Tycho himself in an 
easy attitude seated at a table and directing from a 
book the work of his students. Over his head is an 
automatic celestial globe invented by Tycho and con- 
structed at his own expense in 1590. Over the globe 
is a part of Tycho' s library. On either side are repre- 
sented as hanging small pictures of Tycho's patron, 
Frederick II of Denmark (d. 1588) and Queen 
Sophia. Then other instruments and rooms of the 
observatory are pictured ; Tycho's students, of whom 
there were always at least six or eight, not to men- 
tion younger pupils. There appears also his great 
brass globe six feet in diameter. Then there is pic- 
tured Tycho's chemical laboratory, on which he has 
expended much money. Finally comes one of Tycho's 
hunting dogs very faithful and sagacious ; he serves 
here as a hieroglyph of his master's nobility as well 
as of sagacity and fidelity. The expert architect and 
the two artists who assisted Tycho are delineated in 
the landscape and even in the setting sun in the top- 
most part of the painting, and in the decoration 

The principal use of this largest quadrant was 
the determination of the angle of elevation of the 
stars within the sixth part of a minute, the collinea- 



tion being made by means of one of the sights, the 
parallel horizontal slits in which were aligned with 
the corresponding parts of the circumference of the 
cylinder. The altitude was recorded according to 
the position of the sight attached to the graduated 

Tycho Brahe had a great reverence for Copernicus, 
but he did not accept his planetary system ; and he 
felt that advance in astronomy depended on pains- 
taking observation. For over twenty years under the 
kings of Denmark he had good opportunities for 
pursuing his investigation. The island of Hven be- 
came his property. A thoroughly equipped observa- 
tory was provided, including printing-press and 
workshops for the construction of apparatus. As 
already implied, capable assistants were at the as- 
tronomer's command. In 1598, after having left 
Denmark, Tycho in a splendid illustrated book (As- 
tronomioB Instauratce MecJianicd) gave an account of 
this astronomical paradise on the Insula Venusia as 
he at times called it. The book, prepared for the 
hands of princes, contains about twenty full-page 
colored illustrations of astronomical instruments (in- 
cluding, of course, the mural quadrant), of the ex- 
terior of the observatory of Uraniborg, etc. The 
author had a consciousness of his own worth, and 
deserves the name Tycho the Magnificent. The re- 
sults that he obtained were not unworthy of the 
apparatus employed in his observations, and before 
he died at Prague in 1601, Tycho Brahe had con- 
signed to the worthiest hands the painstaking record 
of his labors. 

Johann Kepler (1571-1630) had been called, as 


the astronomer's assistant, to the Bohemian capital 
in 1600 and in a few months fell heir to Tycho's 
data in reference to 777 stars, which he made the 
basis of the Rudolphine tables of 1627. Kepler's 
genius was complementary to that of his predecessor. 
He was gifted with an imagination to turn observa- 
tions to account. His astronomy did not rest in mere 
description, but sought the physical explanation. He 
had the artist's feeling for the beauty and harmony, 
which he divined before he demonstrated, in the 
number relations of the planetary movements. After 
special studies of Mars based on Tycho's data, he set 
forth in 1609 (Astronomia Novct) (1) that every 
planet moves in an ellipse of which the sun occupies 
one focus, and (2) that the area swept by the ra- 
dius vector from the planet to the sun is proportional 
to the time. Luckily for the success of his investi- 
gation the planet on which he had concentrated his 
attention is the one of all the planets then known, 
the orbit of which most widely differs from a circle. 
In a later work {Harmonica Mundi, 1619) the title 
of which, the Harmonics of the Universe, proclaimed 
his inclination to Pythagorean views, he demon- 
strated (3) that the square of the periodic time of 
any planet is proportional to the cube of its mean 
distance from the sun. 

Kepler's studies were facilitatejijby the invention, 
in 1614 by John Napier, of f logarithm!, which have 

v A V^ ^J 

been said, by abridging tedious-calculations, to dou- 
ble the life of an astronomer. About the same time 
Kepler in purchasing some wine was struck by the 
rough-and-ready method used by the merchant to de- 
termine the capacity of the wine-vessels. He applied 


himself for a few days to the problems of mensura- 
tion involved, and in 1615 published his treatise 
(Stereometria Doliorum) on the cubical contents of 
casks (or wine-jars), a source of inspiration to all 
later writers on the accurate determination of the 
volume of solids. He helped other scientists and was 
himself richly helped. As early as 1610 there had 
been presented to him a means of precision of the 
first importance to the progress of astronomy, 
namely, a Galilean telescope. 

The early history of telescopes shows that the 
effect of combining two lenses was understood by 
scientists long before any particular use was made of 
this knowledge ; and that those who are accredited 
with introducing perspective glasses to the public 
hit by accident upon the invention. Priority was 
claimed by two firms of spectacle-makers in Middel- 
burg, Holland, namely, Zacharias, miscalled Jansen, 
and Lippershey. Galileo heard of the contrivance 
in July, 1609, and soon furnished so powerful an 
instrument of discovery that things seen through 
it appeared more than thirty times nearer and al- 
most a thousand times larger than when seen by the 
naked eye. He was able to make out the mountains 
in the moon, the satellites of Jupiter in rotation, 
the spots on the revolving sun ; but his telescope 
afforded only an imperfect view of Saturn. Of 
course these facts, published in 1610 (Sidereus Nun- 
cius), strengthened his advocacy of the Copernican 
system. Galileo laughingly wrote Kepler that the 
professors of philosophy were afraid to look through 
his telescope lest they should fall into heresy. The 
German astronomer, who had years before written 


on the optics of astronomy, now (1611) produced 
his Dioptrice, the first satisfactory statement of the 
theory of the telescope. 

About 1639 Gascoigne, a young Englishman, in- 
vented the micrometer, which enables an observer to 
adjust a telescope with very great precision. Before 
the invention of the micrometer exactitude was im- 
possible, because the adjustment of the instrument de- 
pended on the discrimination of the naked eye. The 
micrometer was a further advance in exact measure- 
ment. Gascoigne's determinations of, for example, 
the diameter of the sun, bear comparison with the 
findings of even recent astronomical science. 

The history of the^ microscope is closely connected 
with that of the teles^TOper-Iir the first half of the 
seventeenth century the simple microscope came into 
use. It was developed from the convex lens, which, 
as we have seen in a previous chapter, had been 
known for centuries, if not from remote antiquity. 
With the simple microscope Leeuwenhoek before 
1673 had studied the structure of minute animal or- 
ganisms and ten years later had even obtained sight 
of bacteria. Very early in the same century Zacharias 
had presented Prince Maurice, the commander of the 
Dutch forces, and the Archduke Albert, governor 
of Holland, with compound microscopes. Kircher 
(1601-1680) made use of an instrument that repre- 
sented microscopic forms as one thousand times larger 
than their actual size, and by means of the compound 
microscope Malpighi was able in 1661 to see blood 
flowing from the minute arteries to the minute veins 
011 the lung and on the distended bladder of the live 
frog. The Italian microscopist thus, among his many 


achievements, verified by observation what Harvey in 
1628 had argued must take place. 

In this same epoch apparatus of precision developed 
in other fields. Weight clocks had been in use as 
time-measurers since the thirteenth century, but they 
were, as we have seen, difficult to control and other- 
wise unreliable. Even in the seventeenth century 
scientists in their experiments preferred some form 
of water- clock. In 1636 Galileo, in a letter, men- 
tioned the feasibility of constructing a pendulum 
clock, and in 1641 he dictated a description of the 
projected apparatus to his son Vincenzo and to his 
disciple Viviani. He himself was then blind, and he 
died the following year. His instructions were never 
carried into effect. However, in 1657 Christian Huy- 
gens applied the pendulum to weight clocks of the 
old stamp. In 1674 he gave directions for the manu- 
facture of a watch, the movement of which was 
driven by a spring. 

Galileo, to whom the advance in exact science is 
so largely indebted, must also be credited with the 
first apparatus for the measurement of temperatures. 
This was invented before 1603 and consisted of a 
glass bulb with a long stem of the thickness of a 
straw. The bulb was first heated and the stem placed 
in water. The point at which the water, which rose 
in the tube, might stand was an indication of the 
temperature. In 1631 Jean Rey just inverted this 
contrivance, filling the bulb with water. Of course 
these thermoscopes would register the effect of vary- 
ing pressures as well as temperatures, and they soon 
made way for the thermometer and the barometer. 
Before 1641 a true thermometer was constructed by 


sealing the top of the tube after driving out the air 
by heat. Spirits of wine were used in place of water. 
Mercury was not employed till 1670. 

Descartes and Galileo had brought under criticism 
the ancient idea that nature abhors a vacuum. They /> 
knew that the horror vacui was not sufficient to raise 
water in a pump more than about thirty-three feet. 
They had also known that air has weight, a fact 
which soon served to explain the so-called force of 
suction. Galileo's associate Torricelli reasoned that if 
the pressure of the air was sufficient to support a 
column of water thirty-three feet in height, it would 
support a column of mercury of equal weight. Ac- 
cordingly in 1643 he made the experiment of filling 
with mercury a glass tube four feet long closed at 
the upper end, and then opening the lower end in a 
basin of mercury. The mercury in the tube sank until 
its level was about thirty inches above that of the 
mercury in the basin, leaving a vacuum in the upper 
part of the tube. As the specific gravity of mercury 
is 13, Torricelli knew that his supposition had been 
correct and that the column of mercury in the tube 
and the column of water in the pump were owing to 
the pressure or weight of the air. 

Pascal thought that this pressure would be less 
at a high altitude. His supposition was tested on a 
church steeple at Paris, and, later, on the Puy de 
Dome, a mountain in Auvergne. In the latter case a 
difference of three inches in the column of mercury 
was shown at the summit and base of the ascent. 
Later Pascal experimented with the siphon and suc- 
ceeded in explaining it on the principle of atmos- 
pheric pressure. 


Torricelli in the space at the top of his barometer 
(pressure-gauge) had produced what is' called a Tor- 
ricellian vacuum. Otto von Guericke, a burgomaster 
of Magdeburg, who had traveled in France and Italy, 
succeeded in constructing an air-pump by means of 
which air might be exhausted from a vessel. Some of 
his results became widely known in 1657, though his 
works were not published till 1673. 

Robert Boyle (1626-1691), born at Castle Lismore 
in Ireland, was the seventh son and fourteenth child 
of the distinguished first Earl of Cork. He was early 
acquainted with these various experiments in refer- 
ence to the air, as well as with Descartes' theory that 
air is nothing but a congeries or heap of small, and, 
for the most part, flexible particles. In 1659 he wrote 
his New Experiments Physico-Mechanical touching 
the Spring of the Air. Instead of spring, he at times 
used the word elater (e'Xar^p). In this treatise he 
describes experiments with the improved air-pump 
constructed at his suggestion by his assistant, Robert 

One of Boyle's critics, a professor at Louvain, 
while admitting that air had weight and elasticity, 
denied that these were sufficient to account for the 
results ascribed to them. Boyle thereupon published 
a Defence of the Doctrine touching the Spring and 
Weight of the Air. He felt able to prove that the 
elasticity of the air could under circumstances do far 
more than sustain twenty-nine or thirty inches of 
mercury. In support of his view he cited a recent 

He had taken a piece of strong glass tubing fully 
twelve feet in length. (The experiment was made 


by a well-lighted staircase, the tube being suspended 
by strings.) The glass was heated more than a foot 
from the lower end, and bent so that the shorter leg 
of twelve inches was parallel with the longer. The 
former was hermetically sealed at the top and marked 
off in forty-eight quarter-inch spaces. Into the open- 
ing of the longer leg, also graduated, mercury was 
poured. At first only enough was introduced to fill 
the arch, or bent part of the tube below the gradu- 
ated legs. The tube was then inclined so that the air 
might pass from one leg to the other, and equality 
of pressure at the start be assured. Then more mer- 
cury was introduced and every time that the air in the 
shorter leg was compressed a half or a quarter of an 
inch, a record was made of the height of the mercury 
in the long leg of the tube. Boyle reasoned that the 
compressed air was sustaining the pressure of the 
column of mercury in the long leg plus the pressure 
of the atmosphere at the tube's opening, equivalent 
to 29^ 2 g- inches of mercury. Some of the results were 
as follows : When the air in the short tube was com- 
pressed from 12 to 3 inches, it was under a pres- 
sure of H7y 9 g inches of mercury; when compressed 
to 4 it was under pressure of 87i| inches of mer- 
cury ; when compressed to 6, 58 -J--| ; to 9, 39|. Of 
course, when at the beginning of the experiment 
there were 12 inches of air in the short tube, it was 
under the pressure of the atmosphere, equal to that 
of 29-j 2 g- inches of mercury. Boyle with characteristic 
caution was not inclined to draw too general a con- 
clusion from his experiment. However, it was evi- 
dent, making allowance for some slight irregularity 
in the experimental results, that air reduced under 


pressure to one half its original volume, doubles its 
resistance ; and that if it is further reduced to one 
half, for example, from six to three inches, it 
has four times the resistance of common air. In fact, 
Boyle had sustained the hypothesis that supposes 
the pressures and expansions to be in reciprocal pro- 


Sir Robert S. Ball, Great Astronomers. 

Robert Boyle, Works (edited by Thomas Birch). 

Sir David Brewster, Martyrs of Science. 

J. L. E. Dreyer, Tycho Brake. 

Sir Oliver Lodge, Pioneers of Science. 

Flora Masson, Robert Boyle ; a Biography. 




THE period from 1637 to 1687 affords a good 
illustration of the value for the progress of science 
of the cooperation in the pursuit of truth of men of 
different creeds, nationalities, vocations, and social 
ranks. At, or even before, the beginning of that 
period the need of cooperation was indicated by the 
activities of two men of pronouncedly social tempera- 
ment and interests, namely, the French Minim father, 
Mersenne, and the Protestant Prussian merchant, 
Samuel Hartlib. 

Mersenne was a stimulating and indefatigable 
correspondent. His letters to Galileo, Jean Rey, 
Hobbes, Descartes, Gassendi, not to mention other 
scientists and philosophers, constitute an encyclo- 
pedia of the learning of the time. A mathematician 
and experimenter himself, he had a genius for elicit- 
ing discussion and research by means of adroit ques- 
tions. Through him Descartes was drawn into debate 
with Hobbes, and with Gassendi, a champion of the 
experimental method. Through him the discoveries 
of Harvey, Galileo, and Torricelli, as well as of many 
others, became widely known. His letters, in the 
dearth of scientific associations and the absence of 
scientific periodicals, served as a general news agency 
among the learned of his time. It is not surprising 
that a coterie gathered about him at Paris. Hobbes 


spent months in daily intercourse with this group of 
scientists in the winter of 1636-37. 

Hartlib, though he scarcely takes rank with Mer- 
senne as a scientist, was no less influential. Of a gen- 
erous and philanthropic disposition, he repeatedly im- 
poverished himself in the cause of human betterment. 
His chief reliance was on education and improved 
methods of husbandry, but he resembled Horace 
Greeley in his hospitality to any project for the public 

One of Hartlib's chief hopes for the regeneration 
of England, if not of the whole world, rested on the 
teachings of the educational reformer Comenius, a 
bishop of the Moravian Brethren. In 1637, Comenius 
Laving shown himself rather reluctant to put his most 
cherished plans before the public, his zealous disciple 
precipitated matters, and on his own responsibility, 
and unknown to Comenius, issued from his library at 
Oxford Preludes to the Endeavors of Comenius. Be- 
sides Hartlib's preface it contained a treatise by the 
great educator on a Seminary of Christian Pansophy, 
a method of imparting an encyclopedic knowledge 
of the sciences and arts. 

The two friends were followers of the Baconian 
philosophy. They were influenced, as many others 
of the time, by the New Atlantis, which went through 
ten editions between 1627 and 1670, and which out- 
lined a plan for an endowed college with thirty- 
six Fellows divided into groups what would be 
called to-day a university of research endowed by 
the State. It is not surprising to find Comenius 
(who in his student days had been under the influ- 
ence of Alsted, author of an encyclopedia on Baco- 


nian lines) speaking in 1638 on the need of a collegi- 
ate society for carrying on the educational work that 
he himself had at heart. 

In 1641 Hartlib published a work of fiction in 
the manner of the New Atlantis, and dedicated it 
to the Long Parliament. In the same year he urged 
Comenius to come to London, and published another 
work, A Reformation of Schools. He had great in- 
fluence and did not hesitate to use it in his adoptive 
country. Everybody knew Hartlib, and he was ac- 
quainted with all the strata of English society ; for 
although his father had been a merchant, first in 
Poland and later in Elbing, his mother was the 
daughter of the Deputy of the English Company in 
Dantzic and had relatives of rank in London, where 
Hartlib spent most of his life. He gained the good- 
will of the Puritan Government, and even after 
Cromwell's death was working, in conjunction with 
Boyle, for the establishment of a national council of 
universal learning with Wilkins as president. 

When Comenius arrived in London he learned 
that the invitation had been sent by order of Parlia- 
ment. This body was very anxious to take up the 
question of education, especially university educa- 
tion. Bacon's criticisms of Oxford and Cambridge 
were still borne in mind; the legislators considered 
that the college curriculum was in need of reforma- 
tion, that there ought to be more fraternity and cor- 
respondence among the universities of Europe, and 
they even contemplated the endowment by the State 
of scientific experiment. They spoke of erecting a 
university at London, where Gresham College had 
been established in 1597 and Chelsea College in 


1610. It was proposed to place Gresham College, 
the Savoy, or Winchester College, at the disposition 
of the pan sophists. Coraenius thought that nothing 
was more certain than that the design of the great 
Verulam concerning the opening somewhere of a 
universal college, devoted to the advancement of the 
sciences, could be carried out. The impending strug- 
gle, however, between Charles I and the Parliament 
prevented the attempt to realize the pansophic 
dream, and the Austrian Slav, who knew something 
of the horrors of civil war, withdrew, discouraged, 
to the Continent. 

Nevertheless, Hartlib did not abandon the cause, 
but in 1644 broached Milton on the subject of edu- 
cational reform, and drew from him the brief but 
influential tract on Education. In this its author 
alludes rather slightingly to Comenius, who had some- 
thing of Bacon's infelicity in choice of titles and epi- 
thets and who must have seemed outlandish to the 
author of Lycidas and Comus. But Milton joined 
in the criticism of the universities the study of 
words rather than things and advocated an ency- 
clopedic education based on the Greek and Latin 
writers of a practical and scientific tendency (Aris- 
totle, Theophrastus, Cato, Varro, Vitruvius, Seneca, 
and others). He outlined a plan for the establish- 
ment of an institution to be known by the classical 
(and Shakespearian) name " Academy " a plan 
destined to have a great effect on education in the 
direction indicated by the friends of pansophia. 

In this same year Robert Boyle, then an eager 
student of eighteen just returned to England from 
residence abroad, came under the influence of the 


genial Hartlib. In 1646 he writes his tutor inquir- 
ing about books on methods of husbandry and refer- 
ring to the new philosophical college, which valued 
no knowledge but as it had a tendency to use. A few 
months later he was in correspondence with Hartlib in 
reference to the Invisible College, and had written a 
third friend that the corner-stones of the invisible, 
or, as they termed themselves, the philosophical col- 
lege, did now and then honor him with their com- 
pany. These philosophers whom Boyle entertained, 
and whose scientific acumen, breadth of mind, hu- 
mility, and universal good-will he found so congen- 
ial, were the nucleus of the Royal Society of London, 
of which, on its definite organization in 1662, he 
was the foremost member. They had begun to meet 
together in London about 1645, worthy persons in- 
quisitive into natural philosophy Wilkins, inter- 
ested in the navigation of the air and of waters below 
the surface ; Wallis, mathematician and grammarian ; 
the many-sided Petty, political economist, and in- 
ventor of a double-bottomed boat, who had as a youth 
of twenty studied with Hobbes in Paris in 1643, and 
in 1648 was to write his first treatise on industrial 
education at the suggestion of Hartlib, and finally 
make a survey of Ireland and acquire large estates ; 
Foster, professor of astronomy at Gresham College ; 
Theodore Haak from the Pfalz ; a number of medi- 
cal men, Dr. Merret, Dr. Ent, a friend of Harvey, 
Dr. Goddard, who could always be relied upon to 
undertake an experiment, Dr. Glisson, the physiolo- 
gist, author in 1654 of a treatise on the liver (Zte 
Hepate)) and others. They met once a week at 
Goddard's in Wood Street, at the Bull's Head Tav- 
ern in Cheapside, and at Gresham College. 


Dr. Wilkins, the brother-in-law of Cromwell, who 
is regarded by some as the founder of the Royal 
Society, removed to Oxford, as Warden of Wadham, 
in 1649. Here he held meetings and conducted ex- 
periments in conjunction with Wallis, Goddard, 
Petty, Boyle, and others, including Ward (afterwards 
Bishop of Salisbury) interested in Bulliau's Astron- 
omy ; and the celebrated physician and anatomist, 
Thomas Willis, author of a work on the brain (Ce- 
rebri Anatome), and another on fevers (De Febri- 
5ws), in which he described epidemic typhoid as it 
occurred during the Civil War in 1643. 

In the mean time the weekly meetings in London 
continued, and were attended when convenient by 
members of the Oxford group. At Gresham College 
by 1558 it was the custom to remain for discussion 
Wednesdays and Thursdays after Mr. Wren's lecture 
and Mr. Rooke's. During the unsettled state of the 
country after Cromwell's death there was some inter- 
ruption of the meetings, but with the accession of 
Charles II in 1660 there came a greater sense of 
security. New names appear on the records, Lord 
Brouncker, Sir Robert Moray, John Evelyn, Brere- 
ton, Ball, Robert Hooke, and Abraham Cowley. 

Plans were discussed for a more permanent form 
of organization, especially on November 28, 1660, 
when something was said of a design to found a 
college for the promotion of physico-mathematical 
experimental learning. A few months later was pub- 
lished Cowley's proposition for an endowed college 
with twenty professors, four of whom should be 
constantly traveling in the interests of science. The 
sixteen resident professors " should be bound to study 









and teach all sorts of natural, experimental philoso- 
phy, to consist of the mathematics, mechanics, medi- 
cine, anatomy, chemistry, the history of animals, 
plants, minerals, elements, etc.; agriculture, archi- 
tecture, art military, navigation, gardening; the 
mysteries of all trades and improvement of them ; 
the facture of all merchandise, all natural magic or 
divination ; and briefly all things contained in the 
Catalogue of Natural Histories annexed to my Lord 
Bacon's Organon." The early official history of the 
Royal Society (Sprat, 1667) says that this proposal 
hastened very much the adoption of a plan of organi- 
zation. Cowley wished to educate youth and incur 
great expense (X4,000), but " most of the other 
particulars of his draught the Royal Society is now 
putting in practice." 

A charter of incorporation was granted in July, 
1662; and, later, Charles II proclaimed himself 
founder and patron of the Royal Society for the ad- 
vancement of natural science. Charles continued to 
take an interest in this organization, devoted to the 
discovery of truth by the corporate action of men ; 
he proposed subjects for investigation, and asked 
their cooperation in a more accurate measurement 
of a degree of latitude. He showed himself tactful 
to take account of the democratic spirit of scientific 
investigation, and recommended to the Royal Society 
John Graunt, the author of a work on mortality sta- 
tistics first published in 1661. Graunt was a shop- 
keeper of London, and Charles said that if they found 
any more such tradesmen, they should be sure to 
admit them all without more ado. 

It was a recognized principle of the Society freely 


to admit inen of different religions, countries, pro- 
fessions. Sprat said that they openly professed, not 
to lay the foundation of an English, Scotch, Irish, 
Popish or Protestant philosophy, but a philosophy of 
mankind. They sought (hating war as most of them 
did) to establish a universal culture, or, as they 
phrased it, a constant intelligence throughout all civil 
nations. Even for the special purposes of the Society, 
hospitality toward all nations was necessary ; for the 
ideal scientist, the perfect philosopher, should have 
the diligence and inquisitiveness of the northern 
nations, and the cold and circumspect and wary 
disposition of the Italians and Spaniards. Haak 
from the German Palatinate was one of the earliest 
Fellows of the Society, and is even credited by Wallis 
with being the first to suggest the meetings of 1645. 
Oldenburg from Bremen acted as secretary (along 
with Wilkins) and carried on an extensive foreign 
correspondence. Huygens of Holland was one of the 
original Fellows in 1663, while the names of Auzout, 
Sorbiere, the Duke of Brunswick, Bulliau, Cassini, 
Malpighi, Leibnitz, Leeuwenhoek (as well as Win- 
throp and Roger Williams) appear in the records of 
the Society within the first decade. It seemed fitting 
that this cosmopolitan organization should be located 
in the world's metropolis rather than in a mere uni- 
versity town. Sprat thought London the natural seat 
of a universal philosophy. 

r As already implied, the Royal Society was not ex- 
clusive in its attitude toward the different vocations. 
A spirit of true fellowship prevailed in Gresham 
College, as the Society was sometimes called. The 
medical profession, the universities, the churches, the 


court, the army, the navy, trade, agriculture, and 
other industries were there represented. Social par- 
tition walls were broken down, and the Fellows, 
sobered by years of political and religious strife, 
joined, mutually assisting one another, in the advance 
of science for the sake of the common weal. Their 
express purpose was the improvement of all professions 
from the highest general to the lowest artisan. Par- 
ticular attention was paid to the trades, the mechanic 
arts, and the fostering of inventions. One of their 
eight committees dealt with the histories of trades; 
another was concerned with mechanical inventions, 
and the king ordained in 1662 that no mechanical 
device should receive a patent before undergoing 
their scrutiny. A great many inventions emanated 
from the Fellows themselves Hooke's hygroscope; 
Boyle's hydrometer, of use in the detection of coun- 
terfeit coin ; and, again, the tablet anemometer used 
by Sir Christopher Wren (the Leonardo da Vinci 
of his age) to register the velocity of the wind. A 
third committee devoted itself to agriculture, and in 
the Society's museum were collected products and 
curiosities of the shop, mine, sea, etc. One Fellow 
advised that attention should be paid even to the 
least and plainest of phenomena, as otherwise they 
might learn the romance of nature rather than its 
true history. So bent were they on preserving a spirit 
of simplicity and straightforwardness that in their 
sober discussions they sought to employ the language 
of artisans, countrymen, and merchants rather than 
that of wits and scholars. 

Of course there was in the Society a predominance 
of gentlemen of means and leisure, " free and uncon- 


fined." Their presence was thought to serve a double 
purpose. It checked the tendency to sacrifice the 
search of truth to immediate profit, and to lay such 
emphasis on application, as, in the words of a subse- 
quent president of the Society, would make truth, 
and wisdom, and knowledge of no importance for 
their own sakes. In the second place their presence 
was held to check dogmatism on the part of the 
leaders, and subservience on the part of their fol- 
lowers. They understood how difficult it is to trans- 
mit knowledge without putting initiative in jeopardy 
and that quiet intellect is easily dismayed in the 
presence of bold speech. The Society accepted the 
authority of no one, and adopted as its motto Nul- 
lius in Verba. 

In this attitude they were aided by their subject 
and method. Search for scientific truth by labora- 
tory procedure does not favor dogmatism. The early 
meetings were taken up with experiments and dis- 
cussions. The Fellows recognized that the mental 
powers are raised to a higher degree in company 
than in solitude. They welcomed diversity of view 
and the common-sense judgment of the onlooker. As 
in the Civil War the private citizen had held his 
own with the professional soldier, so here the con- 
tribution of the amateur to the discussion was not 
to be despised. They had been taught to shun all 
forms of narrowness and intolerance. They wished 
to avoid the pedantry of the mere scholar, and the 
allied states of mind to which all individuals are lia- 
ble ; they valued the concurring testimony of the 
well-informed assembly. In the investigation of truth 
by the experimental method they even arrived at the 


view that " true experimenting has this one thing 
inseparable from it, never to be a fixed and settled 
art, and never to be limited by constant rules." In 
its incipience at least it is evident that the Royal 
Society was filled with the spirit of tolerance and 
cooperation, and was singularly free from the spirit 
of envy and faction. 

Not least important of the joint labors of the So- 
ciety were its publications, which established con- 
tacts and stimulated research throughout the scien- 
tific world. Besides the Philosophical Transactions, 
which, since their first appearance in 1665, are the 
most important source of information concerning the 
development of modern science, the Royal Society 
printed many important works, among which the 
following will indicate its early achievements : 

Hooke, Robert, Micrographia : or some Physiological 
Descriptions of Minute Bodies made by Magnifying 
Glasses. 1665. 

Graunt, John, Natural and Political Observations . . . 
made upon the Bills of Mortality, with reference to the 
Government, Religion, Trade, Growth, Air, Diseases, and 
the several changes of the City,. 3d edition, 1665. 

Sprat, Thomas, The History of the Royal Society of Lon- 
don, for the Improving of Natural Knowledge. 1667. 

Malpighi, Marcello, Dissertatio epistolica de Bombyce; 
Societati Regies Londini dicata. 1669. (On the silk- 

Evelyn, John, Sylva, or a Discourse of Forest Trees. 1670. 

Horrocks, Jeremiah, Opera [Astronomica] postuma. 1673. 

Malpighi, Marcello, Anatome Plantarum. 1675. 

Willughby, Francis, Ornithology (revised by John Ray). 

Evelyn, John, A Philosophical Discourse of Earth, relating 
to the Culture and Improvement of it for Vegetation. 1676. 

Grew, Nehemiah, The Anatomy of Plants. 1682. 


Willughby, F., Historia Piscium. 1686. 

Ray, John, Historia Plantarum. % vols., 1686-88. 

Flarasteed, John, Tide- Table for 1687. 

Newton, Isaac, Philosophic Naturalis Principia Mathe- 
matica. Autore Is. Newton. Imprimatur: S. Pepys, 
Reg. Soc. Praeses. Julii 5, 1686. 4to. Londini, 1687. 

After the Society had ordered that Newton's 
Mathematical Principles of Natural Philosophy 
should be printed, it was found that the funds had 
been exhausted by the publication of Willughby's 
book on fishes. It was accordingly agreed that Hal- 
ley should undertake the business of looking after 
it, and printing it at his own charge, which he had 
engaged to do. Shortly after, the President of the 
Royal Society, Mr. Samuel Pepys, was desired to 
license Mr. Newton's book. 

It was not merely by defraying the expense of 
publication that Halley contributed to the success 
of the Principia. He, Wren, Hooke, and other Fel- 
lows of the Royal Society, concluded in 1684 that if 
Kepler's third law were true, then the attraction 
exerted on the different planets would vary inversely 
as the square of the distance. What, then, would be 
the orbit of a planet under a central attraction vary- 
ing as the inverse square of the distance ? Halley 
found that Newton had already determined that the 
form of the orbit would be an ellipse. Newton had 
been occupied with the problem of gravitation for 
about eighteen years, but until Halley induced him 
to do so, had hesitated, on account of certain unset- 
tled points, to publish his results. 

He writes: "I began (1666) to think of gravity 
extending to the orb of the moon, . . . and thereby 


compared the force requisite to keep the moon in 
her orb with the force of gravity at the surface of 
the earth, and found them answer pretty nearly.'* 
As early as March of that same year Hooke had 
communicated to the Society an account of experi- 
ments in reference to the force of gravity at differ- 
ent distances from the surface of the earth, either 
upwards or downwards. At this and at every point 
in Newton's discovery the records of co-workers are 
to be found. 

By Flamsteed, the first Royal Astronomer, were 
supplied more accurate data for the determination of 
planetary orbits. To Huygens^ Newton was indebted 
for the laws of centrifugal force. Two doubts had 
made his meticulous mind pause one, of the ac- 
curacy of the data in reference to the measurement 
of the meridian, another, of the attraction of a spher- 
ical shell upon an external point. In the first matter 
the Royal Society, as we have seen, had been long 
interested, and Picard, who had worked on the 
measurement of the earth under the auspices of the 
Academie des Sciences, brought his results, which 
came to the attention of Newton, before the Royal 
Society in 1672. The second difficulty was solved 
by Newton himself in 1685, when he proved that a 
series of concentric spherical shells would act on an 
external point as if their mass were concentrated at 
the center. For his calculations henceforth the plan- 
ets and stars, comets and all other bodies are points 
acted on by lines of force, and " Every particle of 
matter in the universe attracts every other particle 
with a force varying inversely as the square of their 
mutual distances, and directly as the mass of the 


attracting particle." He deduced from this law that 
the earth must be flattened at the poles ; he deter- 
mined the orbit of the moon and of comets ; he ex- 
plained the precession of the equinoxes, the semi- 
diurnal tides, the ratio of the mass of the moon 
and the earth, of the sun and the earth, etc. No 
wonder that Laplace considered that Newton's JPrin- 
cipia was assured a preeminence above all the other 
productions of the human intellect. It is no detrac- 
tion from Newton's merit to say that Halley, Hooke, 
Wren, Huygens, Bulliau, Picard, and many other 
contemporaries (not to mention Kepler and his pred- 
ecessors), as well as the organizations in which 
they were units, share the glory of the result which 
they cooperated to achieve. On the contrary, he 
seems much more conspicuous in the social firma- 
ment because, in spite of the austerity and seeming 
independence of his genius, he formed part of a sys- 
tem, and was under its law. 

Shortly after the founding of the Royal Society, 
correspondence, for which a committee was appointed, 
had been adopted as a means of gaining the coopera- 
tion of men and societies elsewhere. Sir John Moray, 
as President, wrote to Monsieur de Monmort, around 
whom, after the death of Mersenne, the scientific 
coterie in Paris had gathered. This group of men, 
which toward the close of the seventeenth century 
regarded itself, not unnaturally, as the parent soci- 
ety, was in 1666 definitely organized as the Acad- 
emic Royale des Sciences. Finally, Leibnitz, who 
had been a Fellow of the Royal Society as early as 
1673, and had spent years in the service of the 
Dukes of Brunswick, was instrumental in the estab- 





lishraent in 1700 of the Prussian Akademie der 
Wissenschaften at Berlin. 


Sir David Brewster, Memoirs of Sir Isaac Newton. 

E. Conradi, Learned Societies and Academies in Early Times, 
Pedagogical Seminary, vol. xn (1905), pp. 384-426. 

Abraham Cowley, A Proposition for the Advancement of Experi- 
mental Philosophy. 

D. Masson, Life of Milton. Vol. in, chap. n. 

Thomas Sprat, The History of the Royal Society of London. 

The Record of the Royal Society (third edition, 1912). 




OF the Fellows of the Royal Society, Benjamin 
Franklin (1706-1790) is the most representative of 
that age of enlightenment which had its origin in 
Newton's Principia. Franklin represents the eight- 
eenth century in his steadfast pursuit of intellectual, 
social, and political emancipation. And in his long 
fight, calmly waged, against the forces of want, super- 
stition, and intolerance, such as still hamper the de- 
velopment of aspiring youth in America, England, 
and elsewhere, he found science no mean ally. 

There is some reason for believing that the Frank- 
lins (francus free) were of a free line, free from 
that vassalage to an overlord, which in the different 
countries of Europe did not cease to exist with the 
Middle Ages. For hundreds of years they had lived 
obscurely near Northampton. They had early joined 
the revolt against the papal authority. For gener- 
ations they were blacksmiths and husbandmen. Frank- 
lin's great-grandfather had been imprisoned for writ- 
ing satirical verses about some provincial magnate. 
Of the grandfather's four sons the eldest became a 
smith, but having some ingenuity and scholarly abil- 
ity turned conveyancer, and was recognized as able 
and public-spirited. The other three were dyers. 
Franklin's father Josiah and his Uncle Benjamin 
were nonconformists, and conceived the plan of emi- 


grating to America in order to enjoy their way of 
religion with freedom. 

Benjamin, born at Boston, twenty-one years after 
his father's emigration, was the youngest of ten sons, 
all of whom were eventually apprenticed to trades. 
The father was a man of sound judgment who encour- 
aged sensible conversation in his home. Uncle Benja- 
min, who did not emigrate till much later, showed 
interest in his precocious namesake. Both he and the 
maternal grandfather expressed in verse dislike of 
war and intolerance, the one with considerable liter- 
ary skill, the other with a good deal of decent plain- 
ness and manly freedom, as his grandson said. 

Benjamin was intended as a tithe to the Church, 
but the plan was abandoned because of lack of means 
to send him to college. After one year at the Latin 
Grammar School, and one year at an arithmetic and 
writing school, for better or worse, his education of 
that sort ceased; and at the age of ten he began to 
assist in his father's occupation, now that of tallow- 
chandler and soap-boiler. He wished to go to sea, and 
gave indications of leadership and enterprise. His 
father took him to visit the shops of joiners, brick- 
layers, turners, braziers, cutlers, and other artisans, 
thus stimulating in him a delight in handicraft. Fi- 
nally, because of a bookish turn he had been exhibit- 
ing, the boy was bound apprentice to his brother 
James, who about 1720 began to publish the New 
England Courant, the fourth newspaper to be estab- 
lished in America. 

Among the books early read by Benjamin Frank- 
lin were The Pilgrim's Progress, certain historical 
collections, a book on navigation, works of Protestant 


controversy, Plutarch's Lives, filled with the spirit 
of Greek freedom, Dr. Mather's Bonifacius, and 
Defoe's Essay on Projects. The last two seemed to 
give him a way of thinking, to adopt Franklin's 
phraseology, that had an influence on some of the 
principal events of his life. Defoe, an ardent non- 
conformist, educated in one of the Academies (estab- 
lished on Milton's model) and especially trained in 
English and current history, advocated among other 
projects a military academy, an academy for improv- 
ing the vernacular, and an academy for women. He 
thought it barbarous that a civilized and Christian 
country should deny the advantages of learning to 
women. They should be brought to read books and 
especially history. Defoe could not think that God 
Almighty had made women so glorious, with souls 
capable of the same accomplishments with men, and 
all to be only stewards of our houses, cooks, and 

Benjamin still had a hankering for the sea, but he 
recognized in the printing-office and access to books 
other means of escape from the narrowness of the 
Boston of 1720. Between him and another bookish 
boy, John Collins, arose an argument in reference to 
the education of women. The argument took the form 
of correspondence. Josiah Franklin's judicious criti- 
cism led Benjamin to undertake the well-known plan 
of developing his literary style. 

Passing over his reading of the Spectator, however, 
it is remarkable how soon his mind sought out and 
assimilated its appropriate nourishment, Locke's Es- 
say on the, Human Understanding, which began the 
modern epoch in psychology ; the Port Royal Logic, 


prepared by that brilliant group of noble Catholics 
about Pascal ; the works of Locke's disciple Collins, 
whose Discourse on Freethinking appeared in 1713; 
the ethical writings (1708-1713) of Shaftesbury, 
who defended liberty and justice, and detested all 
persecution. A few pages of translation of Xeno- 
phon's Memorabilia gave him a hint as to Socrates' 
manner of discussion, and he made it his own, and 
avoided dogmatism. 

Franklin rapidly became expert as a printer, and 
early contributed articles to the paper. His brother, 
however, to whom he had been bound apprentice for 
a period of nine years, humiliated and beat him. 
Benjamin thought that the harsh and tyrannical 
treatment he received at this time was the means of 
impressing him with that aversion to arbitrary power 
that stuck to him through his whole life. He had a 
strong desire to escape from his bondage, and, after 
five years of servitude, found the opportunity. James 
Franklin, on account of some offensive utterances in 
the New England Courant, was summoned before 
the Council and sent to jail for one month, during 
which time Benjamin, in charge of the paper, took 
the side of his brother and made bold to give the 
rulers some rubs. Later, James was forbidden to pub- 
lish the paper without submitting to the supervision 
of the Secretary of the Province. To evade the diffi- 
culty the New England Courant was published in 
Benjamin's name, James announcing his own retire- 
ment. In fear that this subterfuge might be chal- 
lenged, he gave Benjamin a discharge of his inden- 
tures, but at the same time signed with him a new 
secret contract. Fresh quarrels arose between the 


brothers, however, and Benjamin, knowing that the 
editor dared not plead before court the second con- 
tract, took upon himself to assert his freedom, a step 
which he later regretted as not dictated by the high- 
est principle. 

Unable to find other employment in Boston, con- 
demned by his father's judgment in the matter of the 
contract, some what under public criticism also for his 
satirical vein and heterodoxy, Franklin determined to 
try his fortunes elsewhere. Thus, at the age of sev- 
enteen he made his escape from Boston. 

Unable to find work in New York, he arrived 
after some difficulties in Philadelphia in October, 
1723. He had brought no recommendations from 
Boston ; his supply of money was reduced to one 
Dutch dollar and a shilling in copper. But he that 
hath a Trade hath an Estate (as Poor Richard 
says). His capital was his industry, his skill as a 
printer, his good-will, his shrewd powers of observa- 
tion, his knowledge of books, and ability to write. 
Franklin, recognized as a promising young man by 
the Governor, Sir William Keith, as previously by 
Governor Burnet of New York, had a growing sense 
of personal freedom and self-reliance. 

But increased freedom for those who deserve it 
means increased responsibility ; for it implies the 
possibility of error. Franklin, intent above all 
on the wise conduct of life, was deeply perturbed 
in his nineteenth and twentieth years by a premature 
engagement, in which his ever-passionate nature had 
involved him, by his failure to pay over money col- 
lected for a friend, and by the unsettled state of his 
religious and ethical beliefs. Encouraged by Keith 


to purchase the equipment for an independent print- 
ing-office, Franklin, though unable to gain his fa- 
ther's support for the project, went to London (for 
the ostensible purpose of selecting the stock) at the 
close of the year 1724. 

He remained in London a year and a half, working 
in two of the leading printing establishments of the 
metropolis, where his skill and reliability were soon 
prized. He found the English artisans of that time 
great guzzlers of beer, and influenced some of his 
co-workers to adopt his own more abstinent and hygi- 
enic habits of eating and drinking. About this time 
a book, Religion of Nature Delineated, by William 
Wollaston (great-grandfather of the scientist Wol- 
laston) so roused Franklin's opposition that he wrote 
a reply, which he printed in pamphlet form before 
leaving London in 1726, and the composition of 
which he afterwards regretted. 

He returned to Philadelphia in the employ of a 
Quaker merchant, on whose death he resumed work 
as printer under his former employer. He was given 
control of the office, undertook to make his own type, 
contrived a copper-plate press, the first in America, 
and printed paper money for New Jersey. The sub- 
stance of some lectures in defense of Christianity, in 
courses endowed by the will of Robert Boyle, made 
Franklin a Deist. At the same time his views on 
moral questions were clarified, and he came to recog- 
nize that truth, sincerity, and integrity were of the 
utmost importance to the felicity of life. What he 
had attained by his own independent thought ren- 
dered him ultimately more careful rather than more 
reckless. He now set value on his own character, and 
resolved to preserve it. 


In 1727, still only twenty-one, he drew together a 
number of young men in a sort of club, called the 
" Junto," for mutual benefit in business and for the 
discussion of morals, politics, and natural philosophy. 
They professed tolerance, benevolence, love of truth. 
They discussed the effect on business of the issue of 
paper money, various natural phenomena, and kept 
a sharp look-out for any encroachment on the rights 
of the people. It is not unnatural to find that in a 
year or two (1729), after Franklin and a friend had 
established a printing business of their own and ac- 
quired the Pennsylvania Gazette, the young poli- 
tician championed the cause of the Massachusetts 
Assembly against the claims first put forward by 
Governor Burnet, and that he used spirited language 
referring to America as a nation and clime foreign 
to England. 

In 1730 Franklin bought out his partner, and in 
the same year published dialogues in the Socratic 
manner in reference to virtue and pleasure, which 
show a rapid development in his general views. 
About the same time he married, restored the money 
that had long been owing, and formulated his ethical 
code and religious creed. He began in 1732 the Poor 
Richard Almanacks, said to offer in their homely 
wisdom the best course in existence in practical 

As early as 1729 Franklin had published a pam- 
phlet on Paper Currency. It was a well-reasoned 
discussion on the relation of the issue of paper cur- 
rency to rate of interest, land values, manufactures, 
population, and wages. The want of money discour- 
aged laboring and handicraftsmen. One must con- 


sider the nature and value of money in general. 
This essay accomplished its purpose in the Assembly. 
It was the first of those contributions which, arising 
from Franklin's consideration of the social and indus- 
trial circumstances of the times, gained for him recog- 
nition as the first American economist. It was in the 
same spirit that in 1751 he discussed the question of 
population after the passage of the British Act for- 
bidding the erection or the operation of iron or steel 
mills in the colonies. Science for Franklin was no 
extraneous interest ; he was all of a piece, and it 
was as a citizen of Philadelphia he wrote those essays 
that commanded the attention of Adam Smith, 
Malthus, and Turgot. 

In 1731 he was instrumental in founding the first 
of those public libraries, which (along with a free 
press) have made American tradesmen and farmers 
as intelligent, in Franklin's judgment, as most gen- 
tlemen from other countries, and contributed to the 
spirit with which they defended their liberties. The 
diffusion of knowledge became so general in the 
colonies that in 1766 Franklin was able to tell the 
English legislators that the seeds of liberty were 
universally found there and that nothing could erad- 
icate them. Franklin became clerk of the General 
Assembly and postmaster, improved the paving and 
lighting of the city streets, and established the first 
fire brigade and the first police force in America. 
Then in 1743 in the same spirit of public benefi- 
cence Franklin put forth his Proposal for Promot- 
ing Useful Knowledge among the British Plan- 
tations in America. It outlines his plan for the 
establishment of the American Philosophical Society. 


Correspondence had already been established with 
the Royal Society of London. It is not diffi- 
cult to see in Franklin the same spirit that had ani- 
mated Hartlib, Boyle, Petty, 1 Wilkins, and their 
friends one hundred years before. In fact, Franklin 
was the embodiment of that union of scientific ideas 
and practical skill in the industries that with them 
was merely a pious wish. 

In this same year of 1743 an eclipse of the moon, 
which could not be seen at Philadelphia on account 
of a northeast storm, was yet visible at Boston, 
where the storm came, as Franklin learned from his 
brother, about an hour after the time of observation. 
Franklin, who knew something of fireplaces, ex- 
plained the matter thus : " When I have a fire in 
my chimney, there is a current of air constantly 
flowing from the door to the chimney, but the be- 
ginning of the motion was at the chimney." So in 
a mill-race, water stopped by a gate is like air in a 
calm. When the gate is raised, the water moves for- 
ward, but the motion, so to speak, runs backward. 
Thus the principle was established in meteorology 
that northeast storms arise to the southwest. 

No doubt Franklin was not oblivious of the prac- 
tical value of this discovery, for, as Sir Humphry 
Davy remarked, he in no instance exhibited that 
false dignity, by which philosophy is kept aloof from 
common applications. In fact, Franklin was rather 
apologetic in reference to the magic squares and 

1 See The Advice of W. P. to Mr. Samuel Hartlib for the Ad- 
vancement of some Particular Parts of Learning, in which is advo- 
cated a Gymnasium Mechanicum or a College of Tradesmen with 
fellowships for experts. Petty wanted trade encyclopedias pre- 
pared, and hoped for inventions in abundance. 


circles, with which he sometimes amused his leisure, 
as a sort of ingenious trifling. At the very time 
that the question of the propagation of storms arose 
in his mind he had contrived the Pennsylvania fire- 
place, which was to achieve cheap, adequate, and 
uniform heating for American homes. His aspira- 
tion was for a free people, well sheltered, well fed, 
well clad, well instructed. 

In 1747 Franklin made what is generally consid- 
ered his chief contribution to science. One of his 
correspondents, Collinson (a Fellow of the Royal 
Society and a botanist interested in useful plants, 
through whom the vine was introduced into Vir- 
ginia), had sent to the Library Company at Phila- 
delphia one of the recently invented Leyden jars 
with instructions for its use. Franklin, who had 
already seen similar apparatus at Boston, and his 
friends, set to work experimenting. For months he 
had leisure for nothing else. In this sort of activity 
he had a spontaneous and irrepressible delight. By 
March, 1747, they felt that they had made discov- 
eries, and in July, and subsequently, Franklin re- 
ported results to Collinson. He had observed that a 
pointed rod brought near the jar was much more 
efficacious than a blunt rod in drawing off the 
charge ; also that if a pointed rod were attached to 
the jar, the charge would be thrown off, and accu- 
mulation of charge prevented. Franklin, moreover, 
found that the nature of the charges on the inside 
and on the outside of the glass was different. He 
spoke of one as plus and the other as minus. Again, 
" We say B (and bodies like-circumstanced) is 
electricized positively; A negatively." Dufay had 


recognized two sorts of electricity, obtained by rub- 
bing a glass rod and a stick of resin, and had 
spoken of them as vitreous and resinous. For Frank- 
lin electricity was a single subtle fluid, and electrical 
manifestations were owing to the degree of its pres- 
ence, to interruption or restoration of equilibrium. 

His mind, however, was bent on the use, the ap- 
plications, the inventions, to follow. He contrived 
an " electric jack driven by two Ley den jars and 
capable of carrying a large fowl with a motion fit 
for roasting before a fire." He also succeeded in 
driving an " automatic " wheel by electricity, but he 
regretted not being able to turn his discoveries to 
greater account. 

He thought later in 1748 that there were 
many points of similarity between lightning and the 
spark from a Leyden jar, and suggested an experi- 
ment to test the identity of their natures. The sug- 
gestion was acted upon at Marly in France. An iron 
rod about forty feet long and sharp at the end was 
placed upright in the hope of drawing electricity 
from the storm-clouds. A man was instructed to 
watch for storm-clouds, and to touch a brass wire, 
attached to a glass bottle, to the rod. The conditions 
seemed favorable May 10, 1752 ; sparks between 
the wire and rod and a " sulphurous " odor were 
perceived (the manifestations of wrath !). Franklin's 
well-known kite experiment followed. In 1753 he 
received from the Royal Society a medal for the 
identification and control of the forces of lightning ; 
subsequently he was elected Fellow, became a mem- 
ber of the Academie des Sciences, and of other 
learned bodies. By 1782 there were as many as four 


hundred lightning rods in use in Philadelphia alone, 
though some conservative people regarded their em- 
ployment as impious. Franklin's good-will, clearness 
of conception, and common sense triumphed every- 

One has only to recall that in 1753 he (along 
with Hunter) was in charge of the postal service of 
the colonies, that in 1754 as delegate to the Albany 
Convention he drew up the first plan for colonial 
union, and that in the following year he furnished 
Braddock with transportation for the expedition 
against Fort Duquesne, to realize the distractions 
amid which he pursued science. In 1748 he had 
sold his printing establishment with the purpose of 
devoting himself to physical experiment, but the 
conditions of the time saved him from specialization. 

In 1749 he drew up proposals relating to the 
education of youth in Pennsylvania, which led, two 
years later, to the establishment of the first Ameri- 
can Academy. His plan was so advanced, so demo- 
cratic, springing as it did from his own experience, 
that no secondary school has yet taken full advan- 
tage of its wisdom. The school, chartered in 1753, 
grew ultimately into the University of Pennsylvania. 
Moreover, it became the prototype of thousands of 
schools, which departed from the Latin Grammar 
Schools and the Colleges by the introduction of the 
sciences and practical studies into the curriculum. 

Franklin deserves mention not only in connection 
with economics, meteorology, practical ethics, elec- 
tricity, and pedagogy ; his biographer enumerates 
nineteen sciences to which he made original contri- 
butions or which he advanced by intelligent criti- 


cism. In medicine he invented bifocal lenses and 
founded the first American public hospital ; in navi- 
gation he studied the Gulf Stream and waterspouts, 
and suggested the use of oil in storms and the con- 
struction of ships with water-tight compartments; 
in agriculture he experimented with plaster of Paris 
as a fertilizer and introduced in America the use of 
rhubarb ; in chemistry he aided Priestley's experi- 
ments by information in reference to marsh gas. He 
foresaw the employment of air craft in war. Think- 
ing the English slow to take up the interest in bal- 
loons, he wrote that we should not suffer pride to 
prevent our progress in science. Pride that dines on 
vanity sups on contempt, as Poor Richard says. 
When it was mentioned in his presence that birds 
fly in inclined planes, he launched a half sheet of 
paper to indicate that his previous observations had 
prepared his mind to respond readily to the discov- 
ery. His quickness and versatility made him sought 
after by the best intellects of Europe. 

I pass over his analysis of mesmerism, his con- 
ception of light as dependent (like lightning) on a 
subtle fluid, his experiments with colored cloths, his 
view of the nature of epidemic colds, interest in in- 
oculation for smallpox, in ventilation, vegetarianism, 
a stove to consume its own smoke, the steamboat, 
and his own inventions (clock, harmonica, etc.), for 
which he refused to take out patents. 

However, from the many examples of his scien- 
tific acumen I select one more. As early as 1747 he 
had been interested in geology and had seen speci- 
mens of the fossil remains of marine shells from the 
strata of the highest parts of the Alleghany Moun- 


tains. Later he stated that either the sea had once 
stood at a higher level, or that these strata had been 
raised by the force of earthquakes. Such convul- 
sions of nature are not wholly injurious, since, by 
bringing a great number of strata of different kinds 
to day, they have rendered the earth more fit for 
use, more capable of being to mankind a convenient 
and comfortable habitation. He thought it unlikely 
that a great bouleversement should happen if the 
earth were solid to the center. Rather the surface of 
the globe was a shell resting on a fluid of very great 
specific gravity, and was thus capable of being broken 
and disordered by violent movement. As late as 
1788 Franklin wrote his queries and conjectures 
relating to magnetism and the theory of the earth. 
Did the earth become magnetic by the development 
of iron ore ? Is not magnetism rather interplanetary 
and interstellar ? May not the near passing of a 
comet of greater magnetic force than the earth have 
been a means of changing its poles and thereby 
wrecking and deranging its surface, and raising and 
depressing the sea level ? 

We are not here directly concerned with his polit- 
ical career, in his checking of governors and propri- 
etaries, in his activities as the greatest of American 
diplomats, as the signer of the Declaration of In- 
dependence, of the Treaty of Versailles, and of the 
American Constitution, nor as the president of the 
Supreme Executive Council of Pennsylvania in his 
eightieth, eighty-first, and eighty-second years. When 
he was eighty-four, as president of the Society for 
Promoting the Abolition of Slavery, he signed a 
petition to Congress .against that atrocious debase- 


ment of human nature, and six weeks later, within 
a few weeks of his death, defended the petition with 
his accustomed vigor, humor, wisdom, and ardent 
love of liberty. Turgot wittily summed up Frank- 
lin's career hy saying that he had snatched the light- 
ning from the heavens and the scepter from the 
hands of tyrants (eripuit ccelo fulmen sceptrumque 
tyrannis) ; for both his political and scientific ac- 
tivities sprang from the same impelling emotion 
hatred of the exercise of arbitrary power and desire 
for human welfare. It is no wonder that the French 
National Assembly, promulgates of the Rights of 
Man, paused in their labors to pay homage to the 
simple citizen, who, representing America in Paris 
from his seventy-first till his eightieth year, had by 
his wisdom and urbanity illustrated the best fruits 
of an instructed democracy. 


American Philosophical Society, Record of the Celebration of the 
Two Hundredth Anniversary of the Birth of Benjamin Franklin. 

S. G. Fisher, The True Benjamin Franklin. 

Paul L. Ford, Many-sided Franklin. 

Benjamin Franklin, Complete Works, edited by A. H. Smyth, 
ten volumes, vol. x containing biography. 




THE view expressed by Franklin regarding the 
existence of a fiery mass underlying the crust of the 
earth was not in his time universally accepted. In 
fact, it was a question very vigorously disputed what 
part the internal or volcanic fire played in the for- 
mation and modification of rock masses. Divergent 
views were represented by men who had come to 
the study of geology with varying aims and diverse 
scientific schooling, and the advance of the science 
of the earth's crust was owing in no small measure 
to the interaction of the different sciences which the 
exponents of the various points of view brought to 

Abraham Gottlob Werner (1750-1817) was thei/J 
most conspicuous and influential champion on the' ! 
side of the argument opposed to the acceptance of 
volcanic action as one of the chief causes of geologic 
formations. He was born in Saxony and came of a 
family which had engaged for three hundred years 
in mining and metal working. They were active in 
Saxony when George Agricola prepared his famous 
works on metallurgy and mineralogy inspired by the 
traditional wisdom of the local iron industry. Wer- 
ner's father was an overseer of iron-works, and fur- 
nished his son with mineral specimens as playthings 
before the child could pronounce their names. In 


1769 Werner was invited to attend the newly 
founded Bergakademie (School of Mines) at Frei- 
berg. Three years later he went to the University 
of Leipzig, but, true to his first enthusiasm, wrote 
in 1774 concerning the outward characteristics of 
minerals (Von den ciusserlichen Itennzeichen der 
Fossilieii). The next year he was recalled to Frei- 
berg as teacher of mineralogy and curator of collec- 
tions. He was intent on classification, and might be 
compared in that respect with the naturalist Buffon, 
or the botanist Linnaeus. He knew that chemistry 
afforded a surer, but slower, procedure ; his was a 
practical, intuitive, field method. He observed the 
color, the hardness, weight, fracture of minerals, and 
experienced the joy the youthful mind feels in rapid 
identification. He translated Cronstedt's book on 
mineralogy descriptive of the practical blow-pipe 
tests. After the identification of minerals, Werner 
was interested in their discovery, the location of 
deposits, their geographical distribution, and the rel- 
ative positions of different kinds of rocks, especially 
the constant juxtaposition or superposition of one 
stratum in relation to another. 

Werner was an eloquent, systematic teacher with 
great charm of manner. He kept in mind the prac- 
tical purposes of mining, and soon people flocked to 
Freiberg to hear him from all the quarters of Europe. 
He had before long disciples in every land. He saw 
all phenomena from the standpoint of the geologist. 
He knew the medicinal, as well as the economic, 
value of minerals. He knew the relation of the soil 
to the rocks, and the effects of both on racial char- 
acteristics. Building-stone determines style of archi- 


tecture. Mountains and river-courses have bearing 
on military tactics. He turned his linguistic knowl- 
edge to account and furnished geology with a defi- 
nite nomenclature. Alex. v. Humboldt, Robert Jame- 
son, D'Aubuisson, Weiss (the teacher of Froebel), 
were among his students. Crystallography arid min- 
eralogy became the fashion. Goethe was among the 
enthusiasts, and philosophers like Schelling, under 
the spell of the new science, almost deified the phys- 
ical .universe. 

'Werner considered all rocks as having originated 
by* crystallization, either chemical or mechanical, 
from an aqueous solution a universal primitive 
ocean. He was a Neptunist, as opposed to the Vul- 
canists or Plutonists, who believed in the existence 
of a central fiery massr Werner thought that the 
earth showed universal strata like the layers of an 
onion, the mountains being formed by erosion, sub- 
sidence, cavings-in. In his judgment granite was a 
primitive rock formed previous to animal and vege- 
table life (hence without organic remains) by chem- 
ical precipitation. Silicious slate was formed later 
by mechanical crystallization. At this period organ- 
ized fossils first appear. Sedimentary rocks, like old 
red sandstone, and, according to Werner, basalt, 
are in a third class. Drift, sand, rubble, boulders, 
come next ; and finally volcanic products, like lava, 
ashes, pumice. He was quite positive that all basalt 
was of aqueous origin and of quite recent formation. 
This part of his teaching was soon challenged. He 
was truer to his own essential purposes in writing a 
valuable treatise on metalliferous veins (JDie, Neue 
Theorie der Erzyange), but even there his general 


views are apparent, for he holds that veins are clefts 
filled in from above by crystallization from aqueous 

Before Werner had begun his teaching career at 
Freiberg, Desmarest, the French geologist, had made 
a special study of the basalts of Auvergne. As a 
mathematician he was able to make a trigonometrical 
survey of that district, and constructed a map show- 
ing the craters of volcanoes of different ages, the 
streams of lava following the river courses, and the 
relation of basalt to lava, scoria, ashes, and other 
recognized products of volcanic action. In 1788 he 
was made inspector-general of French manufactures, 
later superintendent of the porcelain works at Sevres. 
He lived to the age of ninety, and whenever Neptu- 
nists would try to draw him into argument, the old 
man would simply say, " Go and see." 

James Hutton (1726-1797), the illustrious Scotch 
geologist, had something of the same aversion to 
speculation that did not rest on evidence ; though he 
was eminently a philosopher in the strictest sense of 
the word, as his three quarto volumes on the Prin- 
ciples of Knowledge bear witness. Hutton was well 
trained at Edinburgh in the High School and Uni- 
versity. In a lecture on logic an illustrative refer- 
ence to aqua regia turned his mind to the study of 
chemistry. He engaged in experiments, and ulti- 
mately made a fortune by a process for the manufac- 
ture of sal ammoniac from coal-soot. In the mean 
time he studied medicine at Edinburgh, Paris, and 
Leyden, and continued the pursuit of chemistry. 
Then, having inherited land in Berwickshire, he 
studied husbandry in Norfolk and took interest in the 


surface of the land and water-courses ; later he pur- 
sued these studies in Flanders. During years of highly 
successful farming, during which Hutton introduced 
new methods in Berwickshire, he was interested in 
meteorology, and in geology as related to soils. In 
1768, financially independent, Dr. Hutton retired 
to reside in Edinburgh. 

He was very genial and sociable and was in close 
association with Adam Smith, the economist, and 
with Black, known in the history of chemistry in con- 
nection with carbonic acid, latent heat, and experi- 
ments in magnesia, quicklime, and other alkaline sub- 
stances (1777). Playfair, professor of mathematics, 
and later of natural philosophy, was Hutton's disciple 
and intimate friend. In the distinguished company 
of the Royal Society of Edinburgh, established in 
1782, the founder of dynamic geology was stimulated 
by these and other distinguished men like William 
Robertson, Lord Kames, and Watt. The first volume 
of the Transactions contains his Theory of Rains, 
and the first statement of his famous Theory of the 
Earth. He was very broad-minded and enthusiastic 
and would rejoice in Watt's improvements of the 
steam engine or Cook's discoveries in the South 
Pacific. Without emphasizing his indebtedness to 
Horace - Benedict de Saussure, physicist, geologist, 
meteorologist, botanist, who gave to Europeans an 
appreciation of the sublime in nature, nor dwelling 
further on the range of Hutton's studies in language, 
general physics, etc., it is already made evident that 
his mind was such as to afford comprehensiveness 
of view. 

He expressed the wish to induce men who had 


sufficient knowledge of the particular branches of 
science, to employ their acquired talents in promoting 
general science, or knowledge of the great system, 
where ends and means are wisely adjusted in the con- 
stitution of the material universe. Philosophy, he 
says, is surely the ultimate end of human knowledge, 
or the object at which all sciences properly must aim. 
Sciences no doubt should promote the arts of life ; 
but, he proceeds, what are all the arts of life, or all 
the enjoyments of mere animal nature, compared with 
the art of human happiness, gained by education and 
brought to perfection by philosophy ? Man must 
learn to know himself ; he must see his station 
among created things ; he must become a moral 
agent. But it is only by studying things in general 
that he may arrive at this perfection of his nature. 
" To philosophize, therefore, without proper science, 
is in vain ; although it is not vain to pursue science, 
without proceeding to philosophy." 

In the early part of 1785 Dr. Hutton presented 
his Theory of the Earth in ninety-six pages of per- 
fectly lucid English. The globe is studied as a ma- 
chine adapted to a certain end, namely, to provide a 
habitable world for plants, for animals, and, above 
all, for intellectual beings capable of the contempla- 
tion and the appreciation of order and harmony. 
Hutton's theory might be made plain by drawing an 
analogy between geological and meteorological ac- 
tivities. The rain descends on the earth ; streams and 
rivers bear it to the sea ; the aqueous vapors, drawn 
from the sea, supply the clouds, and the circuit is com- 
plete. Similarly, the soil is formed from the over- 
hanging mountains ; it is washed as sediment into the 


sea ; it is elevated, after consolidation, into the over- 
hanging mountains. The earth is more than a mech- 
anism, it is an organism that repairs and restores 
itself in perpetuity. Thus Hutton explained the com- 
position, dissolution, and restoration of land upon the 
globe on a general principle, even as Newton had 
brought a mass of details under the single law of 

Again, as Newton had widened man's conception 
of space, so Hutton (and Buffon) enlarged his con- 
ception of time. For the geologist did not under- 
take to explain the origin of things ; he found no 
vestige of a beginning, no prospect of an end; 
and at the same time he conjured up no hypothet- 
ical causes, no catastrophes, or sudden convulsions 
of nature ; neither did he (like Werner) believe that 
phenomena now present, were once absent ; but he 
undertook to explain all geological change by proc- 
esses in action now as heretofore. Countless ages 
were requisite to form the soil of our smiling val- 
leys, but " Time, which measures everything in our 
idea, and is often deficient to our schemes, is to na- 
ture endless and as nothing." The calcareous remains 
of marine animals in the solid body of the earth bear 
witness of a period to which no other species of 
chronology is able to remount. 

Hutton 's imagination, on the basis of what can be 
observed to-day, pictured the chemical and mechan- 
ical disintegration of the rocks ; and saw ice-streams 
bearing huge granite boulders from the declivities of 
primitive and more gigantic Alps. He believed (as 
Desmarest) that rivulets and rivers have constructed, 
and are constructing, their own valley systems, and 


that the denudation ever in progress would be event- 
ually fatal to the sustenance of plant and animal and 
man, if the earth were not a renewable organism, in 
which repair is correlative with waste. 

All strata are sedimentary, consolidated at the 
bottom of the sea by the pressure of the water and 
by subterranean heat. How are strata raised from 
the ocean bed ? By the same subterranean force that 
helped consolidate them. The power of heat for the 
expansion of bodies, is, says Hutton (possibly hav- 
ing in mind the steam engine), so far as we know, 
unlimited. We see liquid stone pouring from the 
crater of a lofty volcano and casting huge rocks into 
mid-air, and yet find it difficult to believe that Vesu- 
vius and Etna themselves have been formed by vol- 
canic action. The interior of the planet may be a 
fluid mass, melted, but unchanged by the action of 
heat. The volcanoes are spiracles or safety-valves, 
and are widely distributed on the surface of the 

Hutton believed that basalt, and the whinstones 
generally, are of igneous origin. Moreover, he put 
granite in the same category, and believed it had 
been injected, as also metalliferous veins, in liquid 
state into the stratified rocks. If his supposition 
were correct, then granite would be found sending 
out veins from its large masses to pierce the strati- 
fied rocks and to crop out where stratum meets stra- 
tum. His conjecture was corroborated at Glen Tilt 
(and in the island of Arran). Hutton was so elated 
at the verification of his view that the Scotch guides 
thought he had struck gold, or silver at the very 
least. In the bed of the river Tilt he could see at 


six points within half a mile powerful veins of red 
granite piercing the black micaceous schist and giv- 
ing every indication of having been intruded from 
beneath, with great violence, into the earlier forma- 

Hutton felt confirmed in his view that in nature 
there is wisdom, system, and consistency. Even the 
volcano and earthquake, instead of being accidents, 
or arbitrary manifestations of divine wrath, are part 
of the economy of nature, and the best clue we have 
to the stupendous force necessary to heave up the 
strata, inject veins of metals and igneous rocks, and 
insure a succession of habitable worlds. 

In 1795 Dr. Hutton published a more elaborate 
statement of his theory in two volumes. In 1802 
Playfair printed Illustrations of the Huttonian 
Theory, a simplification, having, naturally, little 
originality. Before his death In 1797 Hutton de- 
voted his time to reading new volumes by Saussure 
on the Alps, and to preparing a book on The Ele- 
ments of Agriculture. 

Sir James Hall of Dunglass was a reluctant con- 
vert to Hutton's system of geology. Three arguments 
against the Huttonian hypothesis gave him cause for 
doubt. Would not matter solidifying after fusion 
form a glass, a vitreous, rather than a crystalline 
product ? Why do basalts, whinstones, and other sup- 
posedly volcanic rocks differ so much in structure 
from lava? How can marble and other limestones 
have been fused, seeing that they are readily cal- 
cined by heat ? Hutton thought that the compression 
under which the subterranean heat had been applied 
was a factor in the solution of these problems. He 


was encouraged in this view by Black, who, as al- 
ready implied, had made a special study of limestone 
and had demonstrated that lime acquires its caus- 
ticity through the expulsion of carbonic acid. 

Hall conjectured in addition that the rate at which 
the fused mass cooled might have some bearing on 
the structure of igneous rocks. An accident in the 
Leith glass works strengthened the probability of 
his conjecture and encouraged him to experiment. 
A pot of green bottle-glass had been allowed to cool 
slowly with the result that it had a stony, rather a 
vitreous structure. Hall experimenting with glass 
could secure either structure at will by cooling rap- 
idly or slowly, and that with the same specimen. 

He later enclosed some fragments of whin stone in 
a black-lead crucible and subjected it to intense heat 
in the reverberating furnace of an iron foundry. 
(He was in consultation with Mr. Wedgwood on the 
scale of heat, and with Dr. Hope and Dr. Kennedy, 
chemists.) After boiling, and then cooling rapidly, 
the contents of the crucible proved a black glass. 
Hall repeated the experiment, and cooled more slowly. 
The result was an intermediate substance, neither 
glass nor whinstone a sort of slag. Again he heated 
the crucible in the furnace, and removed quickly to 
an open fire, which was maintained some hours and 
then permitted to die out. The result in this case 
was a perfect whinstone. Similar results were ob- 
tained with regular basalts and different specimens 
of igneous rock. 

Hall next experimented with lava from Vesuvius, 
Etna, Iceland, and elsewhere, and found that it be- 
haved like whinstone. Dr. Kennedy by careful chem- 


ical analysis confirmed Hall's judgment of the simi- 
larity of these two igneous products. 

Still later Hall introduced chalk and powdered 
limestone into porcelain tubes, gun barrels, and tubes 
bored in solid iron, which he sealed and brought to 
very high temperatures. He obtained, by fusion, a 
crystalline carbonate resembling marble. Under the 
high pressure in the tube the carbonic acid was re- 
tained. By these and other experiments this doubt- 
ing disciple confirmed Hutton's theory, and became 
one of the great founders of experimental geology. 

It remained for William Smith (1769-1839), 
surveyor and engineer, to develop that species of 
chronology that Hutton had ascribed to organic re- 
mains in the solid strata, to arrange these strata in 
the order of time, and thus to become the founder of 
historic geology. For this task his early education 
might at first glance seem inadequate. His only 
schooling was received in an elementary institution 
in Oxfordshire. He managed, however, to acquire 
some knowledge of geometry, and at eighteen entered, 
as assistant, a surveyor's office. He never attained 
any literary facility, and was always more success- 
ful in conveying his observations by maps, drawings, 
and conversation than by books. 

However, he early began his collection of minerals 
and observed the relation of the soil and the vegeta- 
tion to the underlying rocks. Engaged at the age of 
twenty-four in taking levelings for a canal, he no- 
ticed that the strata were not exactly horizontal, but 
dipped to the east " like slices of bread and butter," 
a phenomenon he considered of scientific significance. 
In connection with his calling he had an opportunity 


of traveling to the north of England and so extended 
the range of his observation, always exceptionally 
alert. For six years he was engaged, as engineer, in 
the construction of the Somerset Coal Canal, where 
he enlarged and turned to practical account his 
knowledge of strata. 

Collectors of fossils (as Lamarck afterwards called 
organic remains) were surprised to find Smith able 
to tell in what formation their different specimens 
had been found, and still more when he enunciated 
the view that " whatever strata were to be found 
in any part of England the same remains would be 
found in it and no other." Moreover, the same order 
of superposition was constant among the strata, as 
Werner, of whom Smith knew nothing, had indeed 
taught. Smith was able to dictate a Tabular View 


of British Strata from coal to chalk with the char- 
acteristic fossils, establishing an order that was found 
to obtain on the Continent of Europe as well as in 

He constructed geological maps of Somerset and 
fourteen other English counties, to which the atten- 
tion of the Board of Agriculture was called. They 
showed the surface outcrops of strata, and were in- 
tended to be of assistance in mining, roadmaking, 
canal construction, draining, and water supply. It 
was at the time of William Smith's scientific dis- 
coveries that the public interest in canal transporta- 
tion was at its height in England, and his study of 
the strata was a direct outcome of his professional 
activity. He called himself a mineral surveyor, and 
he traveled many thousand miles yearly in connec- 
tion with his calling and his interest in the study of 


geology. In 1815 he completed an extensive geolog- 
ical map of England, on which all subsequent geo- 
logical maps have been modeled. It took into account 
the collieries, mines, canals, marshes, fens, and the 
varieties of soil in relation to the substrata. 

Later (1816-1819) Smith published four vol- 
umes, Strata Identified by Organized Fossils, 
which put on record some of his extensive observa- 
tions. His mind was practical and little given to 
speculation. It does not lie in our province here to 
trace his influence on Cuvier and other scientists, 
but to add his name as a surveyor and engineer to 
the representatives of mineralogy, chemistry, physics 
mathematics, philosophy, and various industries and 
vocations, which contributed to the early develop- 
ment of modern geology. 


Sir A. Geikie, Founders of Geology. 

James Hutton, Theory of the Earth. 

Sir Charles Lyell, Principles of Geology. 

John Playfair, Illustrations of the Huttonian Theory, 

K. A. v. Zittel, History of Geology and Paleontology. 




HUTTON had advanced the study of geology by 
concentrating attention on the observable phenomena 
of the earth's crust, and turning away from specula- 
tions about the origin of the world and the relation 
of this sphere to other units of the cosmos. In the 
same century, however, other scientists and phi- 
losophers were attracted by these very problems 
which seemed not to promise immediate or demon- 
strative solution, and through their studies they ar- 
rived at conclusions which profoundly affected the 
science, the ethics, and the religion of the civilized 

Whether religion be defined as a complex feeling 
of elation and humility a sacred fear akin to 
the a3sthetic sense of the sublime; or, as an intel- 
lectual recognition of some high powers which gov- 
ern us below of some author of all things, of some 
force social or cosmic which tends to righteousness ; 
or, as the outcrop of the moral life touched with 
light and radiant with enthusiasm ; or, as partaking 
of the nature of all these : it cannot be denied that 
the eighteenth century contributed to its clarifica- 
tion and formulation, especially through the efforts 
of the German philosopher, Immanuel Kant (1724- 
1804). Yet it is not difficult to show that the 
philosophy of Kant and of those associated with 


him was greatly influenced by the science of the 
time, and that, in fact, in his early life he was a 
scientist rather than a philosopher in the stricter 
sense. His General Natural History and Theory 
of the Heavens, written at the age of thirty-one, 
enables us to follow his transition from science to 
philosophy, and, more especially, to trace the influ- 
ence of his theory of the origin of the heavenly 
bodies on his religious conceptions. 

For part of this theory Kant was indebted to 
Thomas Wright of Durham (1711-1786). Wright 
was the son of a carpenter, became apprenticed to a 
watchmaker, went to sea, later became an engraver, 
a maker of mathematical instruments, rose to afflu- 
ence, wrote a book on navigation, and was offered a 
professorship of navigation in the Imperial Academy 
of St. Petersburg. It was in 1750 that he pub- 
lished, in the form of nine letters, the work that 
stimulated the mind of Kant, An Original Theory 
or New Hypothesis of the Universe. The author 
thought that the revelation of the structure of the 
heavens naturally tended to propagate the principles 
of virtue and vindicate the laws of Providence. He 
regarded the universe as an infinity of worlds acted 
upon by an eternal Agent, and full of beings, tend- 
ing through their various states to a final perfection. 
Who, conscious of this system, can avoid being filled 
with a kind of enthusiastic ambition to contribute 
his atom toward the due admiration of its great and 
Divine Author ? 

Wright discussed the nature of mathematical cer- 
tainty and the various degrees of moral probability 
proper for conjecture (thus pointing to a distinction 


that ultimately became basal in the philosophy of 
Kant). When he claimed that the sun is a vast 
body of blazing matter, and that the most distant 
star is also a sun surrounded by a system of planets, 
he knew that he was reasoning by analogy and not 
enunciating what is immediately demonstrable. Yet 
this multitude of worlds opens out to us an immense 
field of probation and an endless scene of hope to 
ground our expectation of an ever future happiness 
upon, suitable to the native dignity of the awful 
Mind which made and comprehended it. 

The most striking part of Wright's Original Theory 
relates to the construction of the Milky Way, which 
he thought analogous in form to the rings of Saturn. 
From the center the arrangement of the systems and 
the harmony of the movements could be discerned, 
but our solar system occupies a section of the belt, 
and what we see of the creation gives but a confused 
picture, unless by an effort of imagination we attain 
the right point of view. The various cloudy stars or 
light appearances are nothing but a dense accumu- 
lation of stars. What less than infinity can circum- 
scribe them, less than eternity comprehend them, or 
less than Omnipotence produce or support them? 
He passes on to a discussion of time and space with 
regard to the known objects of immensity and dura- 
tion, and in the ninth letter says that, granting the 
creation to be circular or orbicular, we can suppose 
in the center of the whole an intelligent principle, 
the to-all-extending eye of Providence, or, if the 
creation is real, and not merely ideal, a sphere of 
some sort. Around this the suns keep their orbits 
harmoniously, all apparent irregularities arising from 


our eccentric view. Moreover, space is sufficient for 
many such systems. 

Kant resembled his predecessor in his recognition 
of the bearing on moral and religious conceptions 
of the study of the heavens and also in his treat- 
ment of many astronomical details, sometimes merely 
adopting, more frequently developing or modifying, 
the teachings of Wright. He held that the stars 
constitute a system just as much as do the planets of 
our solar system, and that other solar systems and other 
Milky Ways may have been produced in the bound- 
less fields of space. Indeed, he is inclined to identify 
with the latter systems the small luminous elliptical 
areas in the heavens reported by Maupertuis in 1742. 
Kant also accepted Wright's conjecture of a central 
sun or globe and even made selection of one of the 
stars to serve in that office, and taught that the stars 
consist like our sun of a fiery mass. One cannot 
contemplate the world-structure without recognizing 
the excellent orderliness of its arrangement, and 
perceiving the sure indications of the hand of God 
in the completeness of its relations. Reason, he says 
in iheAllgemeineJ^aturgescJiichte^ei.usQsto believe 
it the work of chance. It must have been planned by 
supreme wisdom and carried into effect by Omnipo- 

Kant was especially stimulated by the analogy be- 
tween the Milky Way and the rings of Saturn. He did 
not agree with Wright that they, or the cloudy areas, 
would prove to be stars or small satellites, but rather 
that both consisted of vapor particles. Giving full 
scope to his imagination, he asks if the earth as well 
as Saturn may not have been surrounded by a ring. 


Might not this ring explain the supercelestial waters 
that gave such cause for ingenuity to the medieval 
writers? Not only so, but, had such a vaporous ring 
broken and been precipitated to the earth, it would 
have caused a prolonged Deluge, and the subsequent 
rainbow in the heavens might very well have been 
interpreted as an allusion to the vanished ring, and 
as a promise. This, however, is not Kant's charac- 
teristic manner in supporting moral and religious 

To account for the origin of the solar system, the 
German philosopher assumes that at the beginning 
of all things the material of which the sun, planets, 
satellites, and comets consist, was uncompounded, in 
its primary elements, and filled the whole space in 
which the bodies formed out of it now revolve. This 
state of nature seemed to be the very simplest that 
could follow upon nothing. In a space filled in this 
way a state of rest could not last for more than a 
moment. The elements of a denser kind would, ac- 
cording to the law of gravitation, attract matter of 
less specific gravity. Repulsion, as well as attraction, 
plays a part among the particles of matter dissemi- 
nated in space. Through it the direct fall of particles 
may be diverted into a circular movement about the 
center toward which they are gravitating. 

Of course, in our system the center of attraction 
is the nucleus of the sun. The mass of this body in- 
creases rapidly, as also its power of attraction. Of 
the particles gravitating to it the heavier become 
heaped up in the center. In falling from different 
heights toward this common focus the particles can- 
not have such perfect equality of resistance that no 


lateral movements should be set up. A general circu- 
latory motion is in fact established ultimately in one 
direction about the central mass, which receiving new 
particles from the encircling current rotates in har- 
mony with it. 

Mutual interference in the particles outside the 
mass of the sun prevents all accumulation except in 
one plane and that takes the form of a thin disk con- 
tinuous with the sun's equator. In this circulating 
vaporous disk about the sun differences of density 
give rise to zones not unlike the rings of Saturn. 
These zones ultimately contract to form planets, and 
as the planets are thrown off from the central solar 
mass till an equilibrium is established between the 
centripetal and centrifugal forces, so the satellites in 
turn are formed from the planets. The comets are to 
be regarded as parts of the system, akin to the planets, 
but more remote from the control of the centripetal 
force of the sun. It is thus that Kant conceived the 
nebular hypothesis, accounting (through the forma- 
tion of the heavenly bodies from a cloudy vapor simi- 
lar to that still observable through the telescope) for 
the revolution of the planets in one direction about 
the sun ; the rotation of sun and planets ; the revo- 
lution and rotation of satellites; the comparative 
densities of the heavenly bodies ; the materials in the 
tails of comets ; the rings of Saturn, and other celes- 
tial phenomena. Newton, finding no matter between 
the planets to maintain the community of their move- 
ments, asserted that the immediate hand of God had 
instituted the arrangement without the intervention 
of the forces of Nature. His disciple Kant now under- 
took to explain an additional number of phenomena 


on mechanical principles. Granted the existence of 
matter, he felt capable of tracing the cosmic evolu- 
tion, but at the same time he maintained and strength- 
ened his religious position, and did not assume (like 
Democritus and Epicurus) eternal motion without a 
Creator or the coming together of atoms by accident 
or haphazard. 

It might be objected, he says, that Nature is suffi- 
cient unto itself; but universal laws of the action of 
matter serve the plan of the Supreme Wisdom. There 
is convincing proof of the existence of God in the 
very fact that Nature, even in chaos, cannot proceed 
otherwise than regularly and according to law. Even 
in the essential properties of the elements that consti- 
tuted the chaos, there could be traced the mark of 
that perfection which they have derived from their 
origin, their essential character being a consequence 
of the eternal idea of the Divine Intelligence. Mat- 
ter, which appears to be merely passive and wanting 
in form and arrangement, has in its simplest state a 
tendency to fashion itself by a natural development 
into a more perfect constitution. Matter must be con- 
sidered as created by God in accordance with law and 
as ever obedient to law, not as an independent or hos- 
tile force needing occasional correction. To suppose 
the material world not under law would be to believe 
in a blind fate rather than in Providence. It is Nature's 
harmony and order revealed to our understanding that 
give us a clue to its creation by an understanding of 
the highest order. 

In a work written eight years later Kant sought to 
furnish people of ordinary intelligence with a proof 
of the existence of God. It might seem irrelevant in 


such a production to give an exposition of physical 
phenomena, but, intent on his method of mounting to 
a knowledge of God by means of natural science, he 
here repeats in summarized form his theory of the 
origin of the heavenly bodies. Moreover, the in- 
fluence of his astronomical studies persisted in his 
maturest philosophy, as can be seen in the well-known 
passage at the conclusion of his ethical work, the 
Critique of the Practical Reason (1788) : "There 
are two things that fill my spirit with ever new and 
increasing awe and reverence the more frequently 
and the more intently I contemplate them the star- 
strewn sky above me and the moral law within." His 
religious and ethical conceptions were closely asso- 
ciated with indeed, dependent upon an orderly 
and infinite physical universe. 

In the mathematician, astronomer, physicist, and 
philosopher, J. H. Lambert (1728-1777), Kant 
found a genius akin to his own, and through him 
hoped for a reformation of philosophy on the basis 
of the study of science. Lambert like his contempo- 
rary was a disciple of Newton, and in 1761 he pub- 
lished a book in the form of letters expressing views 
in reference to the Milky Way, fixed stars, central 
sun, very similar to those published by Kant in 
1755. Lambert had heard of Wright's work, so 
similar to his own, a year after the latter was written. 

Comets, now robbed of many of the terrors with 
which ancient superstition endowed them, might, he 
says, seem to threaten catastrophe, by colliding with 
the planets or by carrying off a satellite. But the 
same hand which has cast the celestial spheres in 
space, has traced their course in the heavens, and 


does not allow them to wander at random to distuib 
and destroy each other. Lambert imagines that all 
these bodies have exactly the volume, weight, posi- 
tion, direction, and speed necessary for the avoidance 
of collisions. If we confess a Supreme Ruler who 
brought order from chaos, and gave form to the uni- 
verse ; it follows that this universe is a perfect work, 
the impress, picture, reflex of its Creator's perfec- 
tion. Nothing is left to blind chance. Means are 
fitted to ends. There is order throughout, and in 
this order the dust beneath our feet, the stars above 
our heads, atoms and worlds, are alike compre- 

Laplace in his statement of the .nebular hypothe- 
sis made no mention of Kant. He sets forth, in the 
Exposition of the, Solar System, the astronomical 
data that the theory is designed to explain : the 
movements of the planets in the same direction and 
almost in the same plane ; the movements of the sat- 
ellites in the same direction as those of the planets ; 
the rotation of these different bodies and of the sun 
in the same direction as their projection, and in 
planes little different ; the small eccentricity of the 
orbits of planets and satellites ; the great eccentricity 
of the orbits of comets. How on the ground of these 
data are we to arrive at the cause of the earliest 
movements of the planetary system ? 

A fluid of immense extent must be assumed, em- 
bracing all these bodies. It must have circulated 
about the sun like an atmosphere and, in virtue of 
the excessive heat which was engendered, it may be 
assumed that this atmosphere originally extended 
beyond the orbits of all the planets, and was con- 


tracted by stages to its present form. In its primi- 
tive state the sun resembled the nebulae, which are 
to be observed through the telescope, with fiery cen- 
ters and cloudy periphery. One can imagine a more 
and more diffuse state of the nebulous matter. 

Planets were formed, in the plane of the equator 
and at the successive limits of the nebulous atmos- 
phere, by the condensation of the different zones 
which it abandoned as it cooled and contracted. The 
force of gravity and the centrifugal force sufficed to 
maintain in its orbit each successive planet. From the 
cooling and contracting masses that were to consti- 
tute the planets smaller zones and rings were formed. 
In the case of Saturn there was such regularity in 
the rings that the annular form was maintained ; as 
a rule from the zones abandoned by the planet-mass 
satellites resulted. Differences of temperature and 
density of the parts of the original mass account for 
the eccentricity of orbits, and deviations from the 
plane of the equator. 

In his Celestial Mechanics (1825) Laplace states 
that, according to Herschel's observations, Saturn's 
rotation is slightly quicker than that of its rings. 
This seemed a confirmation of the hypothesis of the 
Exposition du Systeme du Monde. 

When Laplace presented the first edition of this 
earlier work to Napoleon, the First Consul said : 
44 Newton has spoken of God in his book. I have 
already gone through yours, and I have not found 
that name in it a single time." To this Laplace is 
said to have replied : ' 4 First Citizen Consul, I have 
not had need of that hypothesis." The astronomer 
did not, however, profess atheism ; like Kant he felt 


competent to explain on mechanical principles the 
development of the solar system from the point at 
which he undertook it. In his later years he desired 
that the misleading anecdote should be suppressed. 
So far was he from self-sufficiency and dogmatism 
that his last utterance proclaimed the limitations of 
even the greatest intellects : " What we know is little 
enough, what we don't know is immense " (Ce que 
nous connaissons est pen de chose, ce que nous ig- 
norons est immense). 

Sir William Herschel's observations, extended 
over many years, confirmed both the nebular hypoth- 
esis and the theory of the systematic arrangement of 
the stars. He made use of telescopes 20 and 40 feet 
in focal length, and of 18.7 and 48 inches aperture, 
and was thereby enabled, as Humboldt said, to sink 
a plummet amid the fixed stars, or, in his own 
phrase, to gauge the heavens. The Construction of 
the Heavens was always the ultimate object of his 
observations. In a contribution on this subject sub- 
mitted to the Royal Society in 1787 he announced 
the discovery of 466 new nebulae and clusters of 
stars. The sidereal heavens are not to be regarded 
as the concave surface of a sphere, from the center 
of which the observer might be siipposed to look, 
but rather as resembling a rich extent of ground 
or chains of mountains in which the geologist dis- 
covers many strata consisting of various materials. 
The Milky Way is one stratum and in it our sun 
is placed, though perhaps not in the very center of 
its thickness. 

By 1811 he had greatly increased his observations 
of the nebulae and could arrange them in series differ- 


ing in extent, condensation, brightness, general form, 
possession of nuclei, situation, and in resemblance to 
comets and to stars. They ranged from a faint trace 
of extensive diffuse nebulosity to a nebulous star with 
a mere vestige of cloudiness. Herschel was able to 
make the series so complete that the difference be- 
tween the members was no more than could be found 
in a series of pictures of the human figure taken from 
the birth of a child till he comes to be a man in his 
prime. The difference between the diffuse nebulous 
matter and the star is so striking that the idea of 
conversion from one to the other would hardly occur 
to any one without evidence of the intermediate 
steps. It is highly probable that each successive 
state is the result of the action of gravity. 

In his last statement, 1818, he admitted that to his 
telescopes the Milky Way had proved fathomless, 
but on " either side of this assemblage of stars, pre- 
sumably in ceaseless motion round their common 
center of gravity, Herschel discovered a canopy of 
discrete nebulous masses, such as those from the con- 
densation of which he supposed the whole stellar 
universe to be formed." 

In the theory of the evolution of the heavenly bodies, 
as set forth by Kant, Laplace, and Herschel, it was 
assumed that the elements that composed the earth 
are also to be found elsewhere throughout the solar 
system and the universe. The validity of this assump- 
tion was finally established by spectrum analysis. But 
this vindication was in part anticipated, at the begin- 
ning of the nineteenth century, by the analysis of 
meteorites. In these were found large quantities of 
iron, considerable percentages of nickel, as well as 


cobalt, copper, silicon, phosphorus, carbon, magne- 
sium, zinc, and manganese. 


G. F. Becker, Kant as a Natural Philosopher, American Jour- 
nal of Science, vol. v (1898), pp. 97-112. 

W. W. Bryant, A History of Astronomy. 

Agnes M. Clerke, History of Astronomy during the Nineteenth 

Agnes M. Clerke, The Herschels and Modern Astronomy. 

Sir William Herschel, Papers on the Construction of the 
Heavens (Philosophical Transactions, 1784, 1811, etc.). 

A. R. Hinks, Astronomy (Home University Library). 

E. W. Maunders, The Science of the Stars (The People's Books). 



IN the middle of the eighteenth century, when 
Lambert and Kant were recognizing system and 
design in the heavens, little progress had been 
made toward discovering the constitution of matter 
or revealing the laws of the hidden motions of 
things. Boyle had, indeed, made a beginning, not 
only by his study of the elasticity of the air, but by 
his distinction of the elements and compounds and his 
definition of chemistry as the science of the composi- 
tion of substances. How little had been accomplished, 
however, is evident from the fact that in 1750 the 
so-called elements earth, air, fire, water which 
Bacon had marked for examination in 1620, were 
still unanalyzed, and that no advance had been made 
beyond his conception of the nature of heat, the ma- 
jority, indeed, of the learned world holding that heat 
is a substance (variously identified with sulphur, 
carbon, or hydrogen) rather than a mode of motion. 

How scientific thought succeeded in bringing order 
out of confusion and chaos in the subsequent one 
hundred years, and especially at the beginning of the 
nineteenth century, can well be illustrated by these 
very matters, the study of combustion, of heat as a 
form of energy, of the constituents of the atmosphere, 
and of the chemistry of water and of the earth. 

Reference has already been made to Black's dis- 
covery of carbonic acid, and of the phenomena which 


he ascribed to latent heat. The first discovery (1754) 
was the result of the preparation of quicklime in the 
practice of medicine ; the second (1761) involving 
experiments on the temperatures of melting ice, boil- 
ing water, and steam, stimulated Watt in his improve- 
ment of the steam engine. In 1766 Joseph Priestley 
began his study of airs, or gases. In the following year 
observation of work in a brewery roused his curiosity 
in reference to carbonic acid. In 1772 he experi- 
mented with nitric oxide. In the previous century 
Mayow had obtained nitric oxide by treating iron 
with nitric acid. He had then introduced this gas 
into ordinary air confined over water, and found that 
the mixture suffered a reduction of volume. Priestley 
applied this process to the analysis of common air, 
which he discovered to be complex and not simple. 
In 1774, by heating red oxide of mercury by means 
of a burning-glass, he obtained a gas which sup- 
ported combustion better than common air. He in- 
haled it, and experienced a sense of exhilaration. 
" Who can tell," he writes, " but in time this pure air 
may become a fashionable article in luxury ? Hith- 
erto only two mice and myself have had the privilege 
of breathing it." 

The Swedish investigator Scheele had, however, 
discovered this same constituent of the air before 
1773. He thought that the atmosphere must consist 
of at least two gases, and he proved that carbonic 
acid results from combustion and respiration. In 
1772 the great French scientist Lavoisier found that 
sulphur, when burned, gains weight instead of losing 
weight, and five years later he concluded that air 
consists of two gases, one capable of absorption by 


burning bodies, the other incapable of supporting 
combustion. He called the first "oxygen." In his 
Elements of Chemistry Lavoisier gave a clear ex- 
position of his system of chemistry and of the 
discoveries of other European chemists. After his 
studies the atmosphere was no longer regarded as 
mysterious and chaotic. It was known to consist 
largely of oxygen and nitrogen, and to contain in 
addition aqueous vapor, carbonic acid, and ammonia 
which might be brought to earth by rain. 

Cavendish obtained nitrogen from air by using 
nitric oxide to remove the oxygen, and found that 
air consists of about seventy-nine per cent nitrogen 
and about twenty-one per cent oxygen. He also by 
use of the electric spark caused the oxygen and ni- 
trogen of the air to unite to form nitric acid. When 
the nitrogen was exhausted and the redundant oxygen 
removed, " only a small bubble of air remained un- 
absorbed." Similarly Cavendish had found that water 
results from the combination of oxygen and hydrogen. 
Watt had likewise held that water is not an element, 
but a compound of two elementary substances. Thus 
the great masses, earth, air, fire, water, assumed 
as simple by many philosophers from the earliest 
times, were resolving into their constituent parts. At 
the same time other problems were demanding solu- 
tion. What are the laws of chemical combination? 
What is the relation of heat to other forms of energy? 
To the answering of these questions (as of those from 
which these grew) the great manufacturing centers 
contributed, and no city more potently than Man- 
chester through Dalton and his pupil and follower 


John Dalton (1766-1844) was born in Cumber- 
land, went to Kendal to teach school at the age of 
fifteen, and remained in the Lake District of England 
till 1793. In this region, where the annual rainfall 
exceeds forty inches, and in some localities is almost 
tropical, the young student's attention was early 
drawn to meteorology. His apparatus consisted of 
rude home-made rain-gauges, thermometers, and ba- 
rometers. His interest in the heat, moisture, and 
constituents of the atmosphere continued throughout 
life, and Dalton made in all some 200,000 meteoro- 
logical observations. We gain a clue to his motive 
in these studies from a letter written in his twenty- 
second year, in which he speaks of the advantages 
that might accrue to the husbandman, the mariner, 
and to mankind in general if we were able to predict 
the state of the weather with tolerable precision. 

In 1793 Dalton took np his permanent residence 
in Manchester, and in that year appeared his first 
book, Meteorological Observations and Essays. 
Here he deals, among other things, with rainfall, the 
formation of clouds, evaporation, and the distribution 
and character of atmospheric moisture. It seemed 
to him that aqueous vapor always exists as a distinct 
fluid maintaining its identity among the other fluids 
of the atmosphere. He thought of atmospheric mois- 
ture as consisting of minute drops of water, or glob- 
ules among the globules of oxygen and nitrogen. He 
was a disciple of Newton's (to whom, indeed, Dalton 
had some personal likeness), who looked upon matter 
as consisting of " solid, massy, hard, impenetrable, 
movable particles, of such sizes and figures, and with 
such other properties, and in such proportion, as 


most conduced to the end for which God formed 
them." Dalton was so much under the influence of 
the idea that the physical universe is made up of 
these indivisible particles, or atoms, that his biogra- 
pher describes him as thinking corpuscularly. It is 
probable that his imagination was of the visualizing 
type and that he could picture to himself the arrange- 
ment of atoms in elementary and compound substances. 

Now Dalton's master had taught that the atoms of 
matter in a gas (elastic fluid) repel one another by 
a force increasing in proportion as their distance 
diminishes. How did this teaching apply to the at- 
mosphere, which Priestley and others had proved to 
consist of three or more gases? Why does this mix- 
ture appear simple and homogeneous ? Why does not 
the air form strata with the oxygen below and the 
nitrogen above? Cavendish had shown, and Dalton 
himself later proved, that common air, wherever ex- 
amined, contains oxygen and nitrogen in fairly con- 
stant proportions. 

French chemists had sought to apply the principle 
of chemical affinity in explaining the apparent homo- 
geneity of the atmosphere. They supposed that oxygen 
and nitrogen entered into chemical union, the one 
element dissolving the other. The resultant com- 
pound in turn dissolved water ; hence the phenomena 
of evaporation. Dalton tried in vain to reconcile this 
supposition with his belief in the atomic nature of 
matter. He drew diagrams combining an atom of oxy- 
gen with an atom of nitrogen and an atom of aqueous 
vapor. The whole atmosphere could not consist of 
such groups of three because the watery particles 
were but a small portion of the total atmosphere. 


He made a diagram in which one atom of oxygen was 
combined with one atom of nitrogen, but in this case 
the oxygen was insufficient to satisfy all the nitrogen 
of the atmosphere. If the air was made up partly of 
pure nitrogen, partly of a compound of nitrogen and 
oxygen, and partly of a compound of nitrogen, oxy- 
gen, and aqueous vapor, then the triple compound, as 
heaviest, would collect toward the surface of the earth, 
and the double compound and the simple substance 
would form two strata above. If to the compounds 
heat were added in the hope of producing an un- 
stratified mixture, the atmosphere would acquire the 
specific gravity of nitrogen gas. "In short," says 
Dalton, " I was obliged to abandon the hypothesis 
of the chemical constitution of the atmosphere alto- 
gether as irreconcilable to the phenomena." 

He had to return to the conception of the indi- 
vidual particles of oxygen, nitrogen, and water, each 
a center of repulsion. Still he could not explain why 
the oxygen did not gravitate to the lowest place, the 
nitrogen form a stratum above, and the aqueous vapor 
swim upon the top. In 1801, however, Dalton hit 
upon the idea that gases act as vacua for one another, 
that it is only like particles which repel each other, 
atoms of oxygen repelling atoms of oxygen and atoms 
of nitrogen repelling atoms of nitrogen when these 
gases are intermingled in the atmosphere just as 
they would if existing in an unmixed state. " Accord- 
ing to this, we were to suppose that atoms of one kind 
did not repel the atoms of another kind, but only 
those of their own kind." A mixed atmosphere is as 
free from stratifications, as though it were really 


In his analyses of air Dalton made use of the old 
nitric oxide method. In 1802 this led to an inter- 
esting discovery. If in a tube .3 of an inch wide he 
mixed 100 parts of common air with 36 parts of 
nitric oxide, the oxygen of the air combined with 
the nitric oxide, and a residue of 79 parts of atmos- 
pheric nitrogen remained. And if he mixed 100 
parts of common air with 72 of nitric oxide, but in 
a wide vessel over water (in which conditions the 
combination is more quickly effected), the oxygen 
of the air again combined with the nitric oxide and 
a residue of 79 parts of nitrogen again resulted. But 
in the last experiment, if less than 72 parts of nitric 
oxide be employed, there will be a residue of oxygen 
as well as nitrogen ; and if more than 72, there will 
be a residue of nitric oxide in addition to the nitro- 
gen. In the words of Dalton, " oxygen may com- 
bine with a certain portion of nitrous gas [as he 
called nitric oxide], or with twice that portion, but 
with no intermediate portion." 

Naturally these experimental facts were to be ex- 
plained in terms of the ultimate particles of which 
the various gases are composed. In the following 
year Dalton gave graphic representation to his idea 
of the atomic constitution of chemical elements and 

O Hydrogen (D Nitrogen 

O Oxygen Carbon 

(DO Nitric oxide () Carbonic acid 
GCD0 Nitrous oxide 

Much against Dalton' s will his method of indicating 
chemical elements and their combinations had to 


yield to a method introduced by the great Swedish 
chemist Berzelius. In 1837 Dalton wrote: " Ber- 
zelius's symbols are horrifying : a young student in 
chemistry might as soon learn Hebrew as make him- 
self acquainted with them. They appear like a chaos 
of atoms . . . and to equally perplex the adepts of 
science, to discourage the learner, as well as to cloud 
the beauty and simplicity of the Atomic Theory." 

Meantime Dalton's mind had been turning to the 
consideration of the relative sizes and weights of the 
various elements entering into combination with one 
another. He argued that if there be not exactly the 
same number of atoms of oxygen in a given volume 
of air as of nitrogen in the same volume, then the 
sizes of the particles of oxygen must be different 
from those of nitrogen. His interest in the absorp- 
tion of gases by water, in the reciprocal diffusion of 
gases, as well as in the phenomena of chemical com- 
bination, stimulated Dalton to determine the relative 
size and weight of the atoms of the various elements. 
Dalton said nothing of the absolute weight of the 
atom. But on the assumption that when only one 
compound of two elements is known to exist, the 
molecule of the compound consists of one atom of 
each of these elements, he proceeded to investigate 
the relative weights of equal numbers of the two 
sorts of atoms. In 1803 he pursued this investiga- 
tion with remarkable success, and taking hydrogen 
(the lightest gas known to him) as unity, he arrived 
at a statement of the relative atomic weights of 
oxygen, nitrogen, carbon, etc. Dalton thus intro- 
duced into the study of chemical combination a very 
definite idea of quantitative relationship. By him 


the atomic theory of the constitution of matter was 
made definite and applicable to all the phenomena 
known to chemistry. 

During the following months he returned to the 
study of those cases in which the same elements 
combine to form more than one compound. We 
have seen that oxygen unites with nitric oxide to 
form two compounds, and that into the one com- 
pound twice as much nitric oxide (by weight) enters 
as into the other. A like relation was found in the 
weight of oxygen combining with carbon in the two 
compounds carbon monoxide and carbonic acid. In 
the summer of 1804 he investigated the composition 
of two compounds of hydrogen and carbon, marsh 
gas (methane) and olefiant gas (ethylene), and 
found that the first contained just twice as much 
hydrogen in relation to the carbon as the second 
compound contained. In a series of compounds of 
the same two elements one atom of one unites with 
one, two, three, or more atoms of the other ; that is, 
a simple ratio exists between the weights in which 
the second element enters into combination with the 
first. This law of multiple proportions afforded con- 
firmation of Dalton's atomic theory, or chemical 
theory of definite proportions. 

" Without such a theory," says Sir Henry Roscoe, 
" modern chemistry would be a chaos ; with it, order 
reigns supreme, and every apparently contradictory 
discovery only marks out more distinctly the value 
and importance of Dalton's work." In 1826 Sir 
Humphry Davy recognized Dalton's services to sci- 
ence in the following terms : " Finding that in cer- 
tain compounds of gaseous bodies the same elements 


always combined in the same proportions, and that 
when there was more than one combination the 
quantity of the elements always had a constant rela- 
tion, such as 1 to 2, or 1 to 3, or 1 to 4, he 
explained this fact on the Newtonian doctrine of in- 
divisible atoms; and contended that, the relative 
weight of one atom to that of any other atom being 
known, its proportions or weight in all its combina- 
tions might be ascertained, thus making the statics 
of chemistry depend upon simple questions in sub- 
traction or multiplication and enabling the student 
to deduce an immense number of facts from a few 
well-authenticated experimental results. Mr. Dai- 
ton's permanent reputation will rest upon his having 
discovered a simple principle universally applicable 
to the facts of chemistry, in fixing the propor- 
tions in which bodies combine, and thus laying the 
foundation for future labors respecting the sublime 
and transcendental parts of the science of corpuscu- 
lar motion. His merits in this respect resemble those 
of Kepler in astronomy." 

In 1808 Dalton's atomic theory received striking 
confirmation through the investigations of the French 
scientist Gay-Lussac, who showed that gases, under 
similar circumstances of temperature and pressure, 
always combine in simple proportions by volume 
when they act on one another, and that when the 
result of the union is a gas, its volume also is in a 
simple ratio to the volumes of its components. One 
of Dalton's friends summed up the result of Gay- 
Lussac's research in this simple fashion : "His paper 
is on the combination of gases. He finds that all unite 
in equal bulks, or two bulks of one to one of another, 


or three bulks of one to one of another." When 
Dalton had investigated the relative weights with 
which elements combine, he had found no simple 
arithmetical relationship between atomic weight and 
atomic weight. When two or more compounds of the 
same elements are formed, Dalton found, however, 
as we have seen, that the proportion of the element 
added to form the second or third compound is a 
multiple by weight of the first quantity. Gay-Lussac 
now showed that gases, " in whatever proportions 
they may combine, always give rise to compounds 
whose elements by volume are multiples of each 

In 1811 Avogadro, in an essay on the relative 
masses of atoms, succeeded in further confirming 
Dalton's theory and in explaining the atomic basis of 
Gay-Lussac's discovery of simple volume relations in 
the formation of chemical compounds. According to 
the Italian scientist the number of molecules in all 
gases is always the same for equal volumes, or al- 
ways proportional to the volumes, it being taken for 
granted that the temperature and pressure are the 
same for each gas. Dalton had supposed that water 
is formed by the union of hydrogen and oxygen, 
atom for atom. Gay-Lussac found that two volumes 
of hydrogen combined with one volume of oxygen to 
produce two volumes of water vapor. According to 
Avogadro the water vapor contains twice as many 
atoms of hydrogen as of oxygen. One volume of 
hydrogen has the same number of molecules as one 
volume of oxygen. When the two volumes combine 
with one, the combination does not take place, as 
Dalton had supposed, atom for atom, but each half- 


molecule of oxygen combines with one molecule of 
hydrogen. The symbol for water is, therefore, not 
HO but H 2 O. 

Enough has been said to establish Dalton's claim 
to be styled a great lawgiver of chemical science. 
His influence in further advancing definitely formu- 
lated knowledge of physical phenomena can here be 
indicated only in part. In 1800 he wrote a paper 
On the Heat and Cold produced by the Mechanical 
Condensation and Rarefaction of Air. This con- 
tains, according to Dalton's biographer, the first 
quantitative statement of the heat evolved by com- 
pression and the heat evolved by dilatation. His con- 
tribution to the theory of heat has been stated thus : 
The volume of a gas under constant pressure ex- 
pands when raised to the boiling temperature by the 
same fraction of itself, whatever be the nature of 
the gas. In 1798 Count Rumford had reported to 
the Royal Society his Enquiry concerning the Source 
of Heat excited by Friction, the data for which had 
been gathered at Munich. Interested as he was in 
the practical problem of providing heat for the homes 
of the city poor, Rumford had been struck by the 
amount of heat developed in the boring-out of can- 
non at the arsenal. He concluded that anything 
which could be created indefinitely by a process of 
friction could not be a substance, such as sulphur or 
hydrogen, but must be a mode of motion. In the same 
year the youthful Davy was following independently 
this line of investigation by rubbing two pieces of ice 
together, by clock-work, in a vacuum. The friction 
caused the ice to melt, although the experiment was 
undertaken in a temperature of 29 Fahrenheit. 


For James Prescott Joule (1818-1889), who came 
of a family of brewers and was early engaged him- 
self in the brewing industry, was reserved, however, 
the distinction of discovering the exact relation be- 
tween heat and mechanical energy. After having 
studied chemistry under Dalton at Manchester, he 
became engrossed in physical experimentation. In 
1843 he prepared a paper On the Calorific Effects 
of Magneto-Electricity and on the Mechanical Value 
of Heat. In this he dealt with the relations between 
heat and the ordinary forms of mechanical power, 
and demonstrated that the mechanical energy spent 
" in turning a magneto-electrical machine is converted 
into the heat evolved by the passage of the currents 
of induction through its coils ; and, on the other hand, 
that the motive power of the electro-magnetic engine 
is obtained at the expense of the heat due to the 
chemical reactions of the battery by which it is 
worked." In 1844 he proceeded to apply the prin- 
ciples maintained in his earlier study to changes of 
temperature as related to changes in the density of 
gases. He was conscious of the practical, as well as 
the theoretical, import of his investigation. Indeed, 
it was through the determination by this illustrious 
pupil of Dalton's of the amount of heat produced by 
the compression of gases that one of the greatest im- 
provements of the steam engine was later effected. 
Joule felt that his investigation at the same time con- 
firmed the dynamical theory of heat which originated 
with Bacon, and had at a subsequent period been 
so well supported by the experiments of Rumford, 
Davy, and others. 

Already, in this paper of June, 1844, Joule had 


expressed the hope of ascertaining the mechanical 
equivalent of heat with the accuracy that its import- 
ance for physical science demanded. He returned to 
this question again and again. According to his final 
result the quantity of heat required to raise one pound 
of water in temperature by one degree Fahrenheit is 
equivalent to the mechanical energy required to raise 
772.55 pounds through a distance of one foot. Heat 
was thus demonstrated to be a form of energy, the 
relation being constant between it and mechanical 
energy. Mechanical energy may be converted into 
heat ; if heat disappears, some other form of energy, 
equivalent in amount to the heat lost, must replace it. 
The doctrine that a certain quantity of heat is always 
equivalent to a certain amount of mechanical energy 
is only a special case of the Law of the Conserva- 
tion of Energy, first clearly enunciated by Joule and 
Helmholtz in 1847, and generally regarded as the 
most important scientific discovery of the nineteenth 

Roscoe, referring to the two life-sized marble stat- 
ues which face each other in the Manchester Town 
Hall, says with pardonable pride : " Thus honor is 
done to Manchester's two greatest sons to Dai- 
ton, the founder of modern Chemistry and of the 
Atomic Theory, and the discoverer of the laws of 
chemical combining proportions ; to Joule, the founder 
of modern Physics and the discoverer of the Law of 
the Conservation of Energy." 



Alembic Club Reprints, Foundations of the Atomic Theory. 
Joseph Priestley, Experiments and Observations on Different 

Kinds of Air. 
Sir William Ramsay, The Gases of the Atmosphere and the History 

of their Discovery. 

Sir Henry E. Roscoe, John Dalton. 
Sir E. Thorpe, Essays in Historical Chemistry. 



HUMPHKY DAVY (1778-1829) was born in Corn- 
wall, a part of England known for its very mild cli- 
mate and the combined beauty and majesty of its 
scenery. On either side of the peninsula the Atlantic 
in varying mood lies extended in summer sunshine, 
or from its shroud of mist thunders on the black 
cliffs and their time-sculptured sandstones. From the 
coast inland, stretch, between flowered lanes and 
hedges, rolling pasture-lands of rich green made all 
the more vivid by the deep reddish tint of the 
ploughed fields. In Penzance, then a town of about 
three thousand inhabitants, and in its picturesque 
vicinity, the early years of Davy's life were passed. 
Across the bay rose the great vision of the guarded 
mount (St. Michael's) of which Milton's verse 
speaks. Farther to the east lay Lizard Head, the 
southernmost promontory of England, and a few 
miles to the north St. Ives with its sweep of sandy 
beach ; while not far to the west of Penzance Land's 
End stood sentry " 'Twixt two unbounded seas." 
The youthful Davy was keenly alive to the charms 
of his early environment, and his genius was sus- 
ceptible to the belief in supernatural agencies native 
to the imaginative Celtic people among whom he 
was reared. As a precocious child of five he impro- 
vised rhymes, and as a youth set forth in excellent 
verse the glories of Mount's Bay: 


" There did I first rejoice that I was born 
Amidst the majesty of azure seas." 

Davy received what is usually called a liberal edu- 
cation, putting in nine years in the Penzance and 
one year in the Truro Grammar School. His best 
exercises were translations from the classics into 
English verse. He was rather idle, fond of fishing 
(an enthusiasm he retained throughout life) and 
shooting, and less appreciated and beloved by his 
masters than by his school-fellows, who recognized 
his wonderful abilities, sought his aid in their Latin 
compositions (as well as in the writing of letters and 
valentines), and listened eagerly to his imaginative 
tales of wonder and horror. Years later he wrote to 
his mother : " After all, the way in which we are 
taught Latin and Greek does not much influence 
the important structure of our minds. I consider it 
fortunate that I was left much to myself when a 
child, and put upon no particular plan of study, and 
that I enjoyed much idleness at Mr. Coryton's school. 
I perhaps owe to these circumstances the little talents 
that I have and their peculiar application." 

When Davy was about sixteen years old, his fa- 
ther died, leaving the widow and her five children, 
of whom Humphry was the eldest, with very scanty 
provision. The mind of the youth seemed to under- 
go an immediate change. He expressed his resolu- 
tion (which he nobly carried out) to play his part 
as son and brother. Within a few weeks he became 
apprenticed to an apothecary and surgeon, and, hav- 
ing thus found his vocation, drew up his own par- 
ticular plan of self-education, to which he rigidly 
adhered. His brother, Dr. John Davy, bears witness 


that the following is transcribed from a notebook 
of Humphry's, bearing the date of the same year as 
his apprenticeship (1795) : 

1. Theology or Religion ) Taught by Nature. 
Ethics or Moral Virtues ) by Revelation. 

2. Geography. 

3. My Profession 

1. Botany. 2. Pharmacy. 3. Nosology. 4. Anatomy. 
5. Surgery. 6. Chemistry. 

4. Logic. 

5. Language, etc. 

A series of essays which Davy wrote in pursuing 
his scheme of self -culture proves how rapidly his mind 
drew away from the superstitions which character- 
ized the masses of the people among whom he lived. 
He had as a boy been haunted by the fear of mon- 
sters and witches in which the credulous of all classes 
then believed. His notebook shows that he was now 
subjecting to examination the religious and political 
opinions of his time. He composed essays on the 
immortality and immateriality of the soul, on gov- 
ernments, on the credulity of mortals, on the de- 
pendence of the thinking powers on the organiza- 
tion of the body, on the ultimate end of being, on 
happiness, and on moral obligation. He studied the 
writings of Locke, Hartley, Berkeley, Hume, Hel- 
vetius, Condorcet, and Reid, and knew something of 
German philosophy. It was not till he was nineteen 
that Davy entered on the experimental study of 

Guided by the Elements of Lavoisier, encouraged 
by the friendship of Gregory Watt (a son of James 
Watt) and by another gentleman of university edu- 


cation, stimulated by contact with the Cornish min- 
ing industry, Davy pursued this new study with zeal, 
and within a few months had written two essays full 
of daring generalizations on the physical sciences. 
These were published early in 1799. Partly on the 
basis of the ingenious experiment mentioned in the 
preceding chapter, he came to the conclusion that 
" Heat, or that power which prevents the actual 
contact of the corpuscles of bodies, and which is the 
cause of our peculiar sensations of heat and cold, 
may be defined as a peculiar motion, probably a vi- 
bration, of the corpuscles of bodies, tending to sepa- 
rate them." Other passages might be quoted from 
these essays to show how the gifted youth of nineteen 
anticipated the science of subsequent decades, but in 
the main these early efforts were characterized by 
the faults of overwrought speculation and incomplete 
verification. He soon regretted the premature pub- 
lication of his studies. " When I consider," he wrote, 
" the variety of theories that may be formed on the 
slender foundation of one or two facts, I am con- 
vinced that it is the business of the true philosopher 
to avoid them altogether. It is more laborious to 
accumulate facts than to reason concerning them ; 
but one good experiment is of more value than the 
ingenuity of a brain like Newton's." 

In the mean time Davy had been chosen superin- 
tendent of the Pneumatic Institution at Bristol by 
Dr. Beddoes, its founder. It was supported by the 
contributions of Thomas Wedgwood and other dis- 
tinguished persons, and aimed at discovering by 
means of experiment the physiological effect of in- 
haling different gases, or " factitious airs," as they 


were called. The founding of such an establishment 
has been termed a scientific aberration, but the use 
now made in medical practice of oxygen, nitrous 
oxide, chloroform, and other inhalations bears wit- 
ness to the sanity of the sort of research there set 
on foot. Even before going to Bristol, Davy had in- 
haled small quantities of nitrous oxide mixed with 
air, in spite of the fact that this gas had been held 
by a medical man to be the " principle of contagion." 
He now carried on a series of tests, and finally un- 
dertook an extended experiment with the assistance 
of a doctor. In an air-tight or box-chamber he in- 
haled great quantities of the supposedly dangerous 
gas. After he had been in the box an hour and a 
quarter, he respired twenty quarts of pure nitrous 
oxide. He described the experience in the following 
words : 

" A thrilling, extending from the chest to the ex- 
tremities, was almost immediately produced. I felt 
a sense of tangible extension highly pleasurable in 
every limb; my visible impressions were dazzling, 
and apparently magnified ; I heard every sound in 
the room, and was perfectly aware of my situation. 
By degrees, as the pleasurable sensations increased, 
I lost all connection with external things ; trains of 
vivid visible images rapidly passed through my mind, 
and were connected with words in such a manner, as 
to produce perceptions perfectly novel. I existed in 
a world of newly connected and newly modified ideas : 
I theorized, I imagined that I made discoveries. 
When I was awakened from this semi-delirious 
trance by Dr. Kinglake, who took the bag from my 
mouth, indignation and pride were the first feelings 


produced by the sight of the persons about me. My 
emotions were enthusiastic and sublime, and for a 
minute I walked round the room perfectly regard- 
less of what was said to me. As I recovered my 
former state of mind, I felt an inclination to com- 
municate the discoveries I had made during the ex- 
periment. I endeavored to recall the ideas : they 
were feeble and indistinct ; one collection of terms, 
however, presented itself ; and with the most intense 
belief and prophetic manner, I exclaimed to Dr. 
Kinglake, ^Nothing exists but thoughts ! The uni- 
verse is composed of imiiressions, ideas, pleasures 
and pains ! ' 

Davy aroused the admiration and interest of every 
one who met him. A literary man to whom he was 
introduced shortly after his arrival in Bristol spoke 
of the intellectual character of the young man's face. 
His eye was piercing, and when he was not engaged 
in conversation, its expression indicated abstraction, 
as though his mind were pursuing some severe train 
of thought scarcely to be interrupted by external ob- 
jects ; " and," this writer adds, " his ingenuousness 
impressed me as much as his mental superiority." 
Mrs. Beddoes, a gay, witty, and elegant lady, and 
an ardent admirer of the youthful scientist, was a 
sister of Maria Edgeworth. The novelist's tolerance 
of Davy's enthusiasm soon passed into a clear recog- 
nition of his commanding genius. Coleridge, Southey, 
and other congenial friends, whom the chemist met 
under Dr. Beddoes' roof, shared in the general ad- 
miration of his mental and social qualities. Southey 
spoke of him as a miraculous young man, at whose 
talents he could only wonder. Coleridge, when asked 


how Davy compared with the cleverest men he had 
met on a visit to London, replied expressively: 
" Why, Davy can eat them all ! There is an energy, 
an elasticity in his mind, which enables him to seize 
on and analyze all questions, pushing them to their 
legitimate consequences. Every subject in Davy's 
mind has the principle of vitality. Living thoughts 
spring up like turf under his feet." He thought that 
if Davy had not been the first chemist he would 
have been the first poet of the age. Their corre- 
spondence attests the intimate interchange of ideas 
and sentiments between these two men of genius, so 
different, yet with so much in common. 

In 1801 Davy was appointed assistant lecturer 
in chemistry at the Royal Institution (Albe marie 
Street, London), which had been founded from phil- 
anthropic motives by Count Rumford in 1799. Its 
aim was to promote the application of science to the 
common purposes of life. Its founder desired while 
benefiting the poor to enlist the sympathies of the 
fashionable world. Davy, with a zeal for the cause 
of humanity and a clear recognition of the value of 
a knowledge of chemistry in technical industries and 
other daily occupations, lent himself readily to the 
founder's plans. His success as a public expositor 
of science soon won him promotion to the professor- 
ship of chemistry in the new institution, and through 
his influence an interest in scientific investigation 
became the vogue of London society. His popularity 
as a lecturer was so great that his best friends feared 
that the head of the brilliant provincial youth of 
twenty-two might be turned by the adulation of 
which he soon became the object. " I have read," 


writes his brother, "copies of verses addressed to 
him then, . . . anonymous effusions, some of them 
displaying much poetical taste as well as fervor of 
writing, and all showing the influence which his ap- 
pearance and manner had on the more susceptible 
of his audience." 

His study of the tanning industry (1801-1802) 
and his lectures on agricultural chemistry (1 SOS- 
IS 13) are indicative of the early purpose of the 
Koyal Institution and of Davy's lifelong inclination. 
The focus of his scientific interest, however, rested 
on the furtherance of the application of the electrical 
studies of Galvani and Volta in chemical analysis. 
In a letter to the chairman of managers of the Royal 
Institution Volta had in 1800 described his voltaic 
pile made up of a succession of zinc and copper plates 
in pairs separated by a moist conductor, and before 
the end of the same year Nicholson and Carlisle had 
employed an electric current, produced by this newly 
devised apparatus, in the decomposition of water into 
its elements. 

In the spring of the following year the Philosophi- 
cal Magazine states : " We have also to notice a 
course of lectures, just commenced at the institution, 
on a new branch of philosophy we mean Galvanic 
Phenomena. On this interesting branch Mr. Davy 
(late of Bristol) gave the first lecture on the 25th of 
April. He began with the history of Galvanism, de- 
tailed the successive discoveries, and described the dif- 
ferent methods of accumulating influence. . . . He 
showed the effects of galvanism on the legs of frogs, 
and exhibited some interesting experiments on the 
galvanic effects on the solutions of metals in acids." 


In a paper communicated to the Royal Society in 
1806, On Some Chemical Agencies of Electricity, 
Davy put on record the result of years of experiment. 
For example, as stated by his biographer, he had con- 
nected a cup of gypsum with one of agate by means 
of asbestos, and filling each with purified water, had 
inserted the negative wire of the battery in the 
agate cup, and the positive wire in that of the sul- 
phate of lime. In about four hours he had found a 
strong solution of lime in the agate cup, and sul- 
phuric acid in the cup of gypsum. On his reversing 
the arrangement, and carrying on the process for a 
similar length of time, the sulphuric acid appeared in 
the agate cup, and the solution of lime on the opposite 
side. It was thus that he studied the transfer of cer- 
tain of the constituent parts of bodies by the action 
of electricity. "It is very natural to suppose," says 
Davy, " that the repellent and attractive energies are 
communicated from one particle to another particle 
of the same kind, so as to establish a conducting 
chain in the fluid. There may be a succession of 
decompositions and recompositions before the elec- 
trolysis is complete." 

The publication of this paper in 1806 attracted 
much attention abroad, and gained for him in spite 
of the fact that England and France were then at 
war a medal awarded, under an arrangement insti- 
tuted by Napoleon a few years previously, for the best 
experimental work on the subject of electricity. 
" Some people," said Davy, " say I ought not to ac- 
cept this prize; and there have been foolish para- 
graphs in the papers to that effect ; but if the two 
countries or .governments are at war, the men of 


science are not. That would, indeed, be a civil war 
of the worst description : we should rather, through 
the instrumentality of men of science, soften the as- 
perities of national hostility." 

In the following year Davy reported other chemi- 
cal changes produced by electricity; he had suc- 
ceeded in decomposing the fixed alkalis and discover- 
ing the elements potassium and sodium. To analyze 
a small piece of pure potash slightly moist from the 
atmosphere, he had placed it on an insulated platinum 
disk connected with the negative side of a voltaic 
battery. A platinum wire connected with the positive 
side was brought in contact with the upper surface 
of the alkali. " The potash began to fuse at both its 
points of electrization." At the lower (negative) sur- 
face small globules having a high metallic luster like 
quicksilver appeared, some of which burned with ex- 
plosion and flame while others remained and became 
tarnished. When Davy saw these globules of a hith- 
erto unknown metal, he danced about the laboratory 
in ecstasy and for some time was too much excited 
to continue his experiments. 

After recovering from a very severe illness, owing 
in the judgment of some to overapplication to experi- 
mental science, and in his own judgment to a visit 
to Newgate Prison with the purpose of improving its 
sanitary condition, Davy made an investigation of the 
alkaline earths. He failed in his endeavor to obtain 
from these sources pure metals, but he gave names 
to barium, strontium, calcium, and magnesium, con- 
jecturing that the alkaline earths were, like potash 
and soda, metallic oxides. In addition Davy antici- 
pated the isolation of silicon, aluminium, and zirco- 


nium. No doubt what gave special zest to his study 
of the alkalis was the hope of overthrowing the doc- 
trine of French chemists that oxygen was the essen- 
tial element of every acid. Lavoisier had given it, 
indeed, the name oxygen (acid-producer) on that sup- 
position. Davy showed, however, that this element is 
a constituent of many alkalis. 

In 1810 he advanced his controversy by explaining 
the nature of chlorine. Discovered long before by 
the indefatigable Scheele, it bore at the beginning of 
the nineteenth century the name oxymuriatic acid. 
Davy proved that it contained neither ox}^gen nor 
muriatic (hydrochloric) acid (though, as we know, 
it forms, with hydrogen, muriatic acid). He gave 
the name chlorine because of the color of the gas 
(^Xo)jOo?, pale green). Davy studied later the com- 
pounds of fluorine, and though unable to isolate the 
element, conjectured its likeness to chlorine. 

He lectured before the Dublin Society in 1810, 
and again in the following year; on the occasion of 
his second visit receiving the degree of LL.D. from 
Trinity College. He was knighted in the spring of 
1812, and was married to a handsome, intellectual, 
and wealthy lady. He was appointed Honorary Pro- 
fessor of Chemistry at the Royal Institution. His new 
independence gave him full liberty to pursue his 
scientific interests. Toward the close of 1812 he 
writes to Lady Davy: 

"Yesterday I began some new experiments to 
which a very interesting discovery and a slight acci- 
dent put an end. I made use of a compound more 
powerful than gunpowder destined perhaps at some 
time to change the nature of war and influence the 


state of society. An explosion took place which has 
done me no other harm than that of preventing me 
from working this day and the effects of which will 
be gone to-morrow and which I should not mention 
at all, except that you may hear some foolish exag- 
gerated account of it, for it really is not worth men- 
tioning. . . ." The compound on the investigation 
of which he was then engaged is now known as the 
trichloride of nitrogen. 

In the autumn of 1813 Sir Humphry and Lady 
Davy, accompanied by Michael Faraday, who on 
Davy's recommendation had in the spring of the 
same year received a post at the Royal Institution, 
set out, in spite of the continuance of the war, on a 
Continental tour. At Paris Sir Humphry was wel- 
comed by the French scientists with every mark of 
distinction. A substance which had been found in 
the ashes of seaweed two years previously, by a soap- 
boiler and manufacturer of saltpeter, was submitted 
to Davy for chemical examination. Until Davy's 
arrival in Paris little had been done to determine 
its real character. On December 6 Gay-Lussac pre- 
sented a brief report on the new substance, which 
he named iode and considered analogous to chlorine. 
Davy, working with almost incredible rapidity in 
the presence of his rivals, was able a week later to 
sketch the chief characters of this new element, now 
known by the name he chose for it iodine. 

We have passed over his investigation of boracic 
acid, ammonium nitrate, and other compounds; we 
can merely mention in passing his later studies of 
the diamond and other forms of carbon, of the 
chemical constituents of the pigments used by the 


ancients, his investigation of the torpedo fish, and his 
anticipation of the arc light. 

It seems fitting that Sir Humphry Davy should 
be popularly remembered for his invention of the 
miner's safety-lamp. At the beginning of the nine- 
teenth century the development of the iron industry, 
the increasing use of the steam engine and of ma- 
chinery in general led to great activity and enter- 
prise in the working of the coal mines. Colliery ex- 
plosions of fire-damp (marsh gas) became alarmingly 
frequent, especially in the north of England. The 
mine-owners in some cases sought to suppress the 
news of fatalities. A society, however, was formed 
to protect the miners from injury through gas explo- 
sions, and Davy was asked for advice. On his return 
from the Continent in 1815 he applied himself en- 
ergetically to the matter. He visited the mines and 
analyzed the gas. He found that fire-damp explodes 
only at high temperature, and that the flame of this 
explosive mixture will not pass through small aper- 
tures. A miner's lamp was therefore constructed 
with wire gauze about the flame to admit air for 
combustion. The fire-damp entering the gauze 
burned quietly inside, but could not carry a high 
enough temperature through the gauze to explode 
the large quantity outside. To one of the members 
of the philanthropic society which had appealed to 
him Davy wrote : " I have never received so much 
pleasure from the result of any of my chemical la- 
bours ; for I trust the cause of humanity will gain 
something by it." 

Davy was elected President of the Royal Society 
in 1820, and retained that dignity till he felt com- 


pelled by ill health to relinquish it in 1827. u It was 
his wish," says his brother, " to have seen the Royal 
Society an efficient establishment for all the great 
practical purposes of science, similar to the college 
contemplated by Lord Bacon, and sketched in his 
New Atlantis ; having subordinate to it the Royal 
Observatory at Greenwich for astronomy ; the Brit- 
ish Museum, for natural history, in its most exten- 
sive acceptation." 

Sir Humphry Davy, after a life crowded with 
splendid achievements, died at Geneva in 1829 with 
many of his noblest dreams unfulfilled. Fortunately 
in Michael Faraday, who is sometimes referred to 
as the greatest of his discoveries, he had a successor 
who was fully adequate to the task of furthering the 
various investigations that his genius had set on 
foot, and who, to the majority of men of mature 
mind, is no less personally interesting than the Cor- 
nish scientist, poet, and philosopher. 


John Davy, Works of Sir Humphry Davy. 

John Davy, Fragmentary Remains, literary and scientific, of Sir 

Humphry Davy, Bart. 
Bence Jones, Life and Letters of Faraday. 
John Tyndall, Faraday as a Discoverer. 
E. v. Meyer, History of Chemistry. 
S. P. Thompson, Michael Faraday ; his Life and Work. 
Sir Edward Thorpe, Humphry Davy, Poet and Philosopher. 




UNDER this heading we have to consider a single 
illustration the prediction, and the discovery, in 
1846, of the planet Neptune. This event roused 
great enthusiasm among scientists as well as in the 
popular mind, afforded proof of the reliability of the 
Newtonian hypothesis, and demonstrated the preci- 
sion to which the calculation of celestial motions had 
attained. Scientific law appeared not merely as a 
formulation and explanation of observed phenom- 
ena but as a means for the discovery of new truths. 
"Would it not be admirable," wrote Valz to Arago 
in 1835, "to arrive thus at a knowledge of the ex- 
istence of a body which cannot be perceived ? ' 

The prediction and discovery of Neptune, to which 
many minds contributed, and which has been de- 
scribed with a show of justice as a movement of the 
times, arose from the previous discovery of the planet 
Uranus by Sir William Herschel in 1781. After 
that event Bode suggested that it was possible other 
astronomers had observed Uranus before, without 
recognizing it as a planet. By a study of the star 
catalogues this conjecture was soon verified. It was 
found that Flamsteed had made, in 1690, the first 
observation of the heavenly body now called Uranus. 
Ultimately it was shown that there were at least 
seventeen similar observations prior to 1781. 


It might naturally be supposed that these so- 
called ancient observations would lead to a ready 
determination of the planet's orbit, mass, mean dis- 
tance, longitude with reference to the sun, etc. The 
contrary, however, seemed to be the case. When 
Alexis Bouvard, the associate of Laplace, prepared 
in 1821 tables of Uranus, Jupiter, and Saturn on 
the principles of the Mecanique Celeste, he was un- 
able to fix an orbit for Uranus which would harmo- 
nize with the data of ancient and modern observa- 
tions, that is, those antecedent and subsequent to 
HerscheFs discovery in 1781. If he computed an 
orbit from the two sets of data combined, the re- 
quirements of the earlier observations were fairly well 
met, but the later observations were not represented 
with sufficient precision. If on the other hand only 
the modern data were taken into account, tables 
could be constructed meeting all the observations 
subsequent to 1781, but failing to satisfy those prior 
to that date. A consistent result could be obtained 
only by sacrificing the modern or the ancient ob- 
servations. " I have thought it preferable," says Bou- 
vard, " to abide by the second [alternative], as being 
that which combines the greater number of proba- 
bilities in favor of the truth, and I leave it to the 
future to make known whether the difficulty of rec- 
onciling the two systems result from the inaccuracy 
of ancient observations, or whether it depend upon 
some extraneous and unknown influence, which has 
acted on the planet." It was not till three years after 
the death of Alexis Bouvard that the extraneous in- 
fluence, of which he thus gave in 1821 some indica- 
tion, became fully known. 


Almost immediately, however, after the publica- 
tion of the tables, fresh discrepancies arose between 
computation and observation. At the first meeting 
of the British Association in 1832 Professor Airy 
in a paper on the Progress of Astronomy showed 
that observational data in reference to the planet 
Uranus diverged widely from the tables of 1821. 
In 1833 through his influence the " reduction of all 
the planetary observations made at Greenwich from 
1750 ' was undertaken. Airy became Astronomer 
Royal in 1835, and continued to take special inter- 
est in Uranus, laying particular emphasis on the fact 
that the radius vector assigned in the tables to this 
planet was much too small. 

In 1834 the Reverend T. J. Hussey, an amateur 
astronomer, had written to Airy in reference to the 
irregularities in the orbit of Uranus : " The appar- 
ently inexplicable discrepancies between the ancient 
and modern observations suggested to me the possi- 
bility of some disturbing body beyond Uranus, not 
taken into account because unknown. . . . Subse- 
quently, in conversation with Bouvard, I inquired if 
the above might not be the case." Bouvard answered 
that the idea had occurred to him ; indeed, he had 
had some correspondence in reference to it in 1829 
with Hansen, an authority on planetary perturba- 

In the following year Nicolai (as well as Valz) 
was interested in the problem of an ultra-Uranian 
planet in connection with the orbit of Halley's comet 
(itself the subject of a striking scientific prediction 
fulfilled in 1758), now reappearing, and under the 
disturbing influence of Jupiter. In fact, the proba- 


bility of the approaching discovery of a new planet 
soon found expression in popular treatises on astron- 
omy. Mrs. Somerville in her book on The Connec- 
tion of the Physical Sciences (1836) said that the 
discrepancies in the records of Uranus might reveal 
the existence and even " the mass and orbit of a body 
placed for ever beyond the sphere of vision." Simi- 
larly Madler in his Popular Astronomy (1841) 
took the view that Uranus might have been pre- 
dicted by study of the perturbations it produced in 
the orbit of Saturn. Applying this conclusion to a 
body beyond Uranus we, he continued, " may, in- 
deed, express the hope that analysis will one day or 
other solemnize this, her highest, triumph, making 
discoveries with the mind's eye in regions where, in 
our actual state, we are unable to penetrate." 

One should not pass over in this account the labors 
of Eugene Bouvard, the nephew of Alexis, who con- 
tinued to note anomalies in the orbit of Uranus and 
to construct new planetary tables till the very eve 
of the discovery of Neptune. In 1837 he wrote to 
Airy that the differences between the observations 
of Uranus and the calculation were large and were 
becoming continually larger : " Is that owing to a 
perturbation brought about in this planet by some 
body situated beyond it? I don't know, but that's 
my uncle's opinion." 

In 1840 the distinguished astronomer Bessel de- 
clared that attempts to explain the discrepancies 
" must be based on the endeavor to discover an orbit 
and a mass for some unknown planet, of such a na- 
ture, that the resulting perturbations of Uranus 
may reconcile the present want of harmony in the 


observations." Two years later lie undertook re- 
searches in reference to the new planet of whose ex- 
istence he felt certain. His labors, however, were 
interrupted by the death of his assistant Flemming, 
and by his own illness, which proved fatal in 1846, 
a few months before the actual discovery of Nep- 
tune. It is evident that the quest of the new planet 
had become general. The error of Uranus still 
amounted to less than two minutes. This deviation 
from the computed place is not appreciable by the 
naked eye, yet it was felt, by the scientific world, to 
challenge the validity of the Newtonian theory, or 
to foreshadow the addition of still another planet to 
our solar system. 

In July, 1841, John Couch Adams, a young under- 
graduate of St. John's College, Cambridge, whose 
interest had been aroused by reading Airy's paper 
on the Progress of Astronomy, made note of his 
resolution to attempt, after completing his college 
course, the solution of the problem then forming in 
so many minds. After achieving the B.A. as senior 
wrangler at the beginning of 1843, Adams under- 
took to " find the most probable orbit and mass of 
the disturbing body which has acted on Uranus." 
The ordinary problem in planetary perturbations 
calls for the determination of the effect on a known 
orbit exerted by a body of known mass and motion. 
This was an inverse problem ; the perturbation being 
given, it was required to find the position, mass, and 
orbit of the disturbing planet. The data were fur- 
ther equivocal in that the elements of the given 
planet Uranus were themselves in doubt ; the unre- 
liability of its planetary tables, in fact, being the 


occasion of the investigation now undertaken. That 
thirteen unknown quantities were involved indicates 
sufficiently the difficulty of the problem. 

Adams started with the assumptions, not improb- 
able, that the orbit of the unknown planet was a 
circle, and that its distance from the sun was twice 
that of Uranus. This latter assumption was in accord 
with the so-called " Bode's Law," which taught that 
a simple numerical relationship exists between the 
planetary distances (4, 7, 10, 16, 28, 52, 100, 196), 
and that the planets as they lie more remote from 
the sun tend to be more nearly double the distance 
of the next preceding. Adams was encouraged, by 
his first attempt, to undertake a more precise de- 

On his behalf Professor Challis of Cambridge ap- 
plied to Astronomer Royal Airy, who furnished the 
Reductions of the Planetary Observations made at 
Greenwich from 1750 till 1830. In his second en- 
deavor Adams assumed that the unknown planet had 
an elliptical orbit. He approached the solution grad- 
ually, ever taking into account more terms of the per- 
turbations. In September, 1845, he gave the results 
to Challis, who wrote to Airy on the 22d of that 
month that Adams sought an opportunity to submit 
the solution personally to the Astronomer Royal. On 
the 21st of October, 1845, the young mathematician, 
twice disappointed in his attempt to meet Airy, left 
at the Royal Observatory a paper containing the 
elements of the new planet. The position assigned 
to it was within about one degree of its actual place. 

On November 5 Airy wrote to Adams and, among 
other things, inquired whether the solution obtained 


would account for the errors of the radius vector as 
well as for those of heliocentric longitude. For Airy 
this was a crucial question ; but to Adams it seemed 
unessential, and he failed to reply. 

By this time a formidable rival had entered the 
field. Leverrier at the request of Arago had un- 
dertaken to investigate the irregularities in the 
tables of Uranus. In September of the same year 
Eugene Bouvard had presented new tables of that 
planet. Leverrier acted very promptly and systemat- 
ically. His first paper on the problem undertaken 
appeared in the Comptes Rendus of the Academie 
des Sciences November 10, 1845. He had submit- 
ted to rigorous examination the data in reference 
to the disturbing influence of Jupiter and of Saturn 
on the orbit of Uranus. In his second paper, June 
1, 1846, Leverrier reviewed the records of the an- 
cient and modern observations of Uranus (279 in 
all), subjected Bouvard's tables to severe criticism, 
and decided that there existed in the orbit of Uranus 
anomalies that could not be accounted due to errors 
of observation. There must exist some extraneous 
influence, hitherto unknown to astronomers. Some 
scientists had thought that the law of gravitation 
did not hold at the confines of the solar system 
(others that the attractive force of other systems 
might prove a factor), but Leverrier rejected this 
conception. Other theories being likewise discarded 
he asked : " Is it possible that the irregularities of 
Uranus are due to the action of a disturbing planet, 
situated in the ecliptic at a mean distance double 
that of Uranus ? And if so, at what point is this 
planet situated? What is its mass? What are the 


elements of the orbit which it describes ? ' The con- 
clusion reached by the calculations recorded in this 
second paper was that all the so-called anomalies in 
the observations of Uranus could be explained as the 
perturbation caused by a planet with a heliocentric 
longitude of 252 on January 1, 1800. This would 
correspond to 325 January 1, 1847. 

Airy received Leverrier's second paper on June 
23, and was struck by the fact that the French mathe- 
matician assigned the same place to the new planet 
as had Adams in the preceding October. He wrote 
to Leverrier in reference to the errors of the radius 
vector and received a satisfactory and sufficiently 
compliant reply. At one time the Astronomer Royal 
had felt very skeptical about the possibility of the 
discovery which his own labors had contributed to 
advance. He had always, to quote his own rather 
nebulous statement, considered the correctness of 
a distant mathematical result to be the subject of 
moral rather than of mathematical evidence. Now 
that corroboration of Adams's results had arrived, 
he felt it urgent to make a telescopic examination of 
that part of the heavens indicated by the theoretical 
findings of Adams and Leverrier. He accordingly 
wrote to Professor Challis, July 9, requesting him 
to employ for the purpose the great Northumberland 
equatorial of the Cambridge Observatory. 

Professor Challis had felt, to use his own language, 
that it was so novel a thing to undertake observa- 
tions in reliance upon merely theoretical deductions, 
that, while much labor was certain, success appeared 
very doubtful. Nevertheless, having received fresh 
instructions from Adams relative to the theoretical 


place of the new planet, he began observations July 
29. On August 4 in fixing certain reference points 
he noted, but mistook for a star, the new planet. On 
August 12, having directed the telescope in accord- 
ance with Adams's instructions he again noted the 
same heavenly body, as a star. Before Challis had 
compared the results of the observation of August 
12 with the results of an observation of the same 
region made on July 30, and arrived at the inference 
that the body in question, being absent in the latter 
observation, was not a star but a planet, the prize of 
discovery had fallen into the hands of another ob- 

On August 31 had appeared Leverrier's third 
paper, in which were stated the new planet's orbit, 
mass, distance from the sun, eccentricity, and longi- 
tude. The true heliocentric longitude was given as 
326 32' for January 1, 1847. This determination 
placed the planet about 5 to the east of star 8 of Cap- 
ricorn. Leverrier said it might be recognized by its 
disk, which, moreover, would subtend a certain angle. 

The systematic and conclusive character of Lever- 
rier's research, submitted to one of the greatest acad- 
emies of science, carried conviction to the minds of 
astronomers. The learned world felt itself on the eve 
of a great discovery. Sir John Herschel, in an ad- 
dress before the British Association on September 
10, said that the year past had given prospect of a 
new planet. " We see it as Columbus saw America 
from the shores of Spain. Its movements have been 
felt trembling along the far-reaching line of our 
analysis with a certainty hardly inferior to ocular 


On September 18 Leverrier sent a letter to Dr. 
Galle, of the Berlin Observatory, which was provided 
with a set of star maps, prepared at the instance of 
Bessel. Galle replied one week later. " The planet, 
of the position of which you gave the indication, 
really exists. The same day that I received your let- 
ter [September 23] I found a star of the eighth 
magnitude, which was not inscribed in the excellent 
map (prepared by Dr. Bremiker) belonging to the 
collection of star maps of the Royal Academy of 
Berlin. The observation of the following day showed 
decisively that it was the planet sought." It was only 
57' from the point predicted. 

Arago said that the discovery made by Leverrier 
was one of the most brilliant manifestations of the 
precision of modern astronomic science. It would en- 
courage the best geometers to seek with renewed ardor 
the eternal truths which, in Pliny's phrase, are latent 
in the majesty of theory. 

Professor Challis received Leverrier's third paper 
on September 29, and in the evening turned his mag- 
nificent refractor to the part of the heavens that Le- 
verrier had so definitely and so confidently indicated. 
Among the three hundred stars observed Challis was 
struck by the appearance of one which presented a 
disk and shone with the brightness of a star of the 
eighth magnitude. This proved to be the planet. On 
October 1 Challis heard that the German observer 
had anticipated him. 

Arago, while recognizing the excellent work done 
by Adams in his calculations, thought that the fact that 
the young mathematician had failed to publish his re- 
sults should deprive him of any share whatever in the 


glory of the discovery of the new planet, and that 
history would confirm this definite judgment. Arago 
named the new planet after the French discoverer, 
but soon acquiesced in the name Neptune, which has 
since prevailed. 

Airy, in whose possession Adams's results had re- 
mained for months unpublished and unheeded, wrote 
Leverrier: " You are to be recognized beyond doubt 
as the predictor of the planet's place." A vigorous 
official himself, Airy was deeply impressed by the 
calm decisiveness and definite directions of the French 
mathematician. " It is here, if I mistake not, that we 
see a character far superior to that of the able, or 
enterprising, or industrious mathematician ; it is here 
that we see the philosopher." This explains, if any- 
thing could, his view that a distant mathematical re- 
sult is the subject of ethical rather than of mathe- 
matical evidence. 

Adams's friends felt that he had not received from 
either of the astronomers, to whom he confided his 
results, the kind of help or advice he should have re- 
ceived. Challis was kindly, but wanting in initiative. 
Although he had command of the great Northumber- 
land telescope, he had no thought of commencing the 
search in 184 5, for, without mistrusting the evidence 
which the theory gave of the existence of the planet, 
it might be reasonable to suppose that its position 
was determined but roughly, and that a search for it 
must necessarily be long and laborious. In the view 
of Simon Newcomb, 1 Adams's results, which were 
delivered at the Greenwich Observatory October 21, 
1845, were so near to the mark that a few hours' 

1 See article " Neptune," Encyc. Brit. 


close search could not have failed to make the planet 

Both Adams and Leverrier had assumed as a 
rough approximation at starting that the orbit of the 
new planet was circular and that, in accordance with 
Bode's Law, its distance was twice that of Uranus. 
S. C. Walker, of the Smithsonian Institution, Wash- 
ington, was able to determine the elements of the 
orbit of Neptune accurately in 1847. In February 
of that year he had found (as had Petersen of Al- 
tona about the same time) that Lalande had in May, 
1795, observed Neptune and mistaken it for a fixed 
star, When Lalande's records in Paris were studied, 
it was found that he had made two observations of 
Neptune on May 8 and 10. Their failure to agree 
caused the observer to reject one and mark the other 
as doubtful. Had he repeated the observation, he 
might have noted that the star moved, and was in 
reality a planet. 

Neptune's orbit is more nearly circular than that 
of any of the major planets except Venus. Its dis- 
tance is thirty times that of the earth from the sun 
instead of thirty-nine times, as Bode's Law would 
require. That generalization was a presupposition 
of the calculations leading to the discovery. It was 
then rejected like a discredited ladder. Man's con- 
ception of the universe is widened at the thought 
that the outmost known planet of our solar system 
is about 2,796,000,000 miles from the sun and 
requires about 165 years for one revolution. 

Professor Peirce, of Harvard University, point- 
ing to the difference between the calculations of 
Leverrier and the facts, put forward the view that 


the discovery made by Galle must be regarded as a 
happy accident. This view, however, has not been 


Sir Robert Ball, Neptune's Jubilee Year, Scientific American, 

Supplement, Oct. 10, 1896. 

Sir Robert Ball, The Story of the Heavens, chap. xv. 
B. A. Gould, Report on the History of the Discovery of Neptune, 

Smithsonian Contributions to Knowledge, 1850. 
Robert Grant, History of Physical Astronomy. 
Simon Newcomb, Popular Astronomy. 
Benjamin Peirce, Proceedings of the American Academy of Arts 

and Sciences, vol. i, pp. 57-68, 144, 285, 338-41, etc. 




SIR CHARLES LYELL, in his Principles of Ge- 
ology, the first edition of which appeared in 1830- 
1833, says : " If it be true that delivery be the first, 
second, and third requisite in a popular orator, it is 
no less certain that travel is of first, second, and 
third importance to those who desire to originate 
just and comprehensive views concerning the struc- 
ture of our globe." The value of travel to science 
in general might very well be illustrated by Lyell's 
own career, his study of the mountainous regions of 
France, his calculation of the recession of Niagara 
Falls and of the sedimentary deposits of the Missis- 
sippi, his observations of the coal formations of Nova 
Scotia, and of the composition of the Great Dismal 
Swamp of Virginia suggestive of the organic origin 
of the carboniferous rocks. 

Although it is not with Lyell that we have here 
principally to deal, it is not irrelevant to say that 
the main purpose of his work was to show that all 
past changes in the earth's crust are referable to 
causes now in operation. Differing from Hutton as 
to the part played in those changes by subterranean 
heat, Lyell agreed with his forerunner in ascribing 
geological transformations to " the slow agency of 
existing causes." He was, in fact, the leader of the 
uniformitarians and opposed those geologists who 


held that the contemporary state of the earth's crust 
was owing to a series of catastrophes, stupendous 
exhibitions of natural force to which recent history 
offered no parallel. Also enlightened as to the sig- 
nificance of organic remains in stratified rock, Lyell 
in 1830 felt the need of further knowledge in refer- 
ence to the relation of the plants and animals rep- 
resented in the fossils to the fauna and flora now 

It is to Lyell's disciple, Charles Darwin, however, 
that we turn for our main illustration of the value 
of travel for comprehensive scientific generalization. 
Born, like another great liberator, on February 12, 
1809, Darwin was only twenty-two years old when 
he received appointment as naturalist on H.M.S, 
Beagle, about to sail from Devonport on a voyage 
around the world. The main purpose of the expedi- 
tion, under command of the youthful Captain Fitz- 
roy, three or four years older than Darwin, was to 
make a survey of certain coasts in South America 
and the Pacific Islands, and to carry a line of chron- 
ometrical measurements about the globe. Looking 
back in 1876 on this memorable expedition, the 
naturalist wrote, "The voyage of the Beagle has 
been by far the most important event in my life, 
and has determined my whole career." In spite of 
the years he had spent at school and college he re- 
garded this experience as the first real training or 
education of his mind. 

Darwin had studied medicine at Edinburgh, but 
found surgery distasteful. He moved to Cambridge, 
with the idea of becoming a clergyman of the Estab- 
lished Church. As a boy he had attended with his 


mother, daughter of Josiah Wedgwood, the Unita- 
rian services. At Cambridge he graduated without 
distinction at the beginning of 1831. It should be 
said, however, that the traditional studies were par- 
ticularly ill suited to his cast of mind, that he had 
not been idle, and had developed particular diligence 
in different branches of science, and above all as a 

He was six feet tall, fond of shooting and hunt- 
ing, and able to ride seventy-five or eighty miles 
without tiring. He had shown himself at college 
fond of company, and a little extravagant. He was, 
though a sportsman, extremely humane ; had a hor- 
ror of inflicting pain, and such repugnance at the 
thought of slavery that he quarreled violently with 
Captain Fitzroy when the latter condoned the abom- 
ination. Darwin was not, however, of a turbulent 
disposition. Sir James Sulivan, who had accompa- 
nied the expedition as second lieutenant, said many 
years after : " I can confidently express my belief 
that during the five years in the Beagle, he was 
never known to be out of temper, or to say one un- 
kind or hasty word of or to any one." 

Darwin's father was remarkable for his powers 
of observation, while the grandfather, Erasmus Dar- 
win, is well known for his tendency to speculation. 
Charles Darwin possessed both these mental charac- 
teristics in an eminent degree. One who has con- 
versed with him reports that what impressed him 
most in meeting the great naturalist was his clear 
blue eyes, which seemed to possess almost telescopic 
vision, and that the really remarkable thing about 
Darwin was that he saw more than other people. At 


the same time it will scarcely be denied that his 
vision was as much marked by insight as by careful 
observation, that his reasoning was logical and sin- 
gularly tenacious, and his imagination vivid. It was 
before this supreme seer that the panorama of ter- 
restrial creation was displayed during a five years' 

No one can read Darwin's Journal descriptive of 
the voyage of the Beagle and continue to entertain 
any doubts in reference to his aesthetic sense and 
poetic appreciation of the various moods of nature. 
Throughout the voyage the scenery was for him the 
most constant and highest source of enjoyment. His 
emotions responded to the glories of tropical vegeta- 
tion in the Brazilian forests, and to the sublimity of 
Patagonian wastes and the forest-clad hills of Tierra 
del Fuego. " It is easy," writes the gifted adoles- 
cent, " to specify the individual objects of admira- 
tion in these grand scenes ; but it is not possible to 
give an adequate idea of the higher feelings of won- 
der, astonishment, and devotion, which fill and ele- 
vate the mind." Similarly, on the heights of the 
Andes, listening to the stones borne seaward day 
and night by the mountain torrents, Darwin re- 
marked : " The sound spoke eloquently to the geolo- 
gist ; the thousands and thousands of stones, which 
striking against each other, made the one dull uni- 
form sound, were all hurrying in one direction. It 
was like thinking on time, where the minute that 
now glides past is irrecoverable. So was it with 
these stones, the ocean is their eternity, and each 
note of that wild music told of one more step towards 
their destiny." 


When the Beagle left Devonport, December 27, 
1831, the young naturalist was without any theory, 
and when the ship entered Falmouth harbor, Octo- 
ber 2, 1836, though he felt the need of a theory in 
reference to the relations of the various species of 
plants and animals, he had not formulated one. It 
was not till 1859 that his famous work on the Origin 
of Species appeared. He went merely as a collector, 
and frequently in the course of the voyage felt a 
young man's misgivings as to whether his collections 
would be of value to his Cambridge professors and 
other mature scientists. 

Professor Henslow, the botanist, through whom 
Darwin had been offered the opportunity to accom- 
pany the expedition, had presented his pupil with 
the first volume of Lyell's Principles of Geology. 
(Perhaps, after Lyell, the most potent influence on 
Darwin's mind at this time was that of Hurnboldt 
and other renowned travelers, whose works he read 
with avidity.) At the Cape Verde Islands he made 
some interesting observations of a white calcareous 
stratum which ran for miles along the coast at a 
height of about forty-five feet above the water. It 
rested on volcanic rocks and was itself covered with 
basalt, that is, lava which had crystallized under the 
sea. It was evident that subsequently to the forma- 
tion of the basalt that portion of the coast contain- 
ing the white stratum had been elevated. The shells 
in the stratum were recent, that is, corresponded to 
those still to be found on the neighboring coast. It 
occurred to Darwin that the voyage might afford 
material for a book on geology. Later in the voy- 
age, having read portions of his Journal to Captain 


Fitzroy, Darwin was encouraged to believe that this 
also might prove worthy of publication. 

Darwin's account of his adventures and manifold 
observations is so informal, so rich in detail, as not 
to admit of summary. His eye took in the most di- 
verse phenomena, the color of the sea or of rivers, 
clouds of butterflies and of locusts, the cacique with his 
little boy clinging to the side of a horse in headlong 
flight, the great earthquake on the coast of Chile, the 
endless variety of plant and animal life, the supersti- 
tion of savage and padre, the charms of Tahiti, the 
unconscious humor of his mountain guides for whom 
at an altitude of eleven thousand feet " the cursed 
pot (which was a new one) did not choose to boil 
potatoes " all found response in Darwin's open 
mind ; everything was grist to his mill. Any selec- 
tion from the richness of the original is almost sure 
to show a tendency not obvious in the Journal. On 
the other hand, it is just such multiplicity of phe- 
nomena as the Journal mirrors that impels every 
orderly mind to seek for causes, for explanation. 
The human intellect cannot rest till law gives form 
to the wild chaos of fact. 

No disciple of Lyell could fail to be convinced 
of the immeasurable lapse of time required for the 
formation of the earth's crust. For this principle 
Darwin found abundant evidence during the years 
spent in South America. On the heights of the Andes 
he found marine shell fossils at a height of fourteen 
thousand feet above sea-level. That such an eleva- 
tion of submarine strata should be achieved by forces 
still at Nature's command might well test the faith 
of the most ardent disciple. Of how great those 


forces are Darwin received demonstration on the 
coast of Chile in 1835. Under date of February 12, 
he writes : " This day has been memorable in the 
annals of Valdivia for the most severe earthquake 
experienced by the oldest inhabitant. ... A bad 
earthquake destroys our oldest associations ; the 
earth, the very emblem of solidity, has moved be- 
neath our feet like a thin crust over a fluid." He 
observed that the most remarkable effect of this 
earthquake was the permanent elevation of the land. 
Around the Bay of Concepcion it was raised two or 
three feet, while at the island of Santa Maria the 
elevation was much greater ; u on one part Captain 
Fitzroy found beds of putrid mussel shells still 
adhering to the rocks, ten feet above high-water 
mark." On the same day the volcanoes of South 
America were active. The area from under which 
volcanic matter was actually erupted was 720 miles 
in one line and 400 in another at right angles to it. 
Great as is the force at work, ages are required to 
produce a range of mountains like the Cordilleras ; 
moreover, progress is not uniform and subsidence 
may alternate with elevation. It was on the princi- 
ple of the gradual subsidence (and elevation) of the 
bed of the Pacific Ocean that Darwin accounted for 
the formation of coral reefs. Nothing u is so unsta- 
ble as the level of the crust of this earth." 

Closely associated with the evidence of the im- 
mensity of the force of volcanic action and the in- 
finitude of time elapsed, Darwin had testimony of 
the multitude of plant and animal species, some gi- 
gantic, others almost infinitely small, some living, 
others extinct. We know that his thought was greatly 


affected by his discovery in Uruguay and Patagonia 
of the fossil remains of extinct mammals, all the 
more so because they seemed to bear relationship to 
particular living species and at the same time to 
show likeness to other species. The Toxodon (bow- 
tooth), for example, was a gigantic rodent whose 
fossil remains were discovered iu the same region 
where Darwin found living the capybara, a rodent 
as large as a pig ; at the same time the extinct species 
showed in its structure certain affinities to the Eden- 
tata (sloths, ant-eaters, armadillos). Other fossils 
represented gigantic forms distinctly of the edentate 
order and comparable to the Cape ant-eater and the 
Great Armadillo (Dasypus gig as). Again, remains 
were found of a thick-skinned non-ruminant with a 
certain structural likeness to the CamelidaB, to which 
the living species of South American ruminants, the 
guanacos, belong. 

Why have certain species ceased to exist ? As the 
individual sickens and dies, so certain species become 
rare and extinct. Darwin found in Northern Pat- 
agonia evidence of the Equus curvidens, an extinct 
species of native American horse. What had caused 
this species to die out? Imported horses were intro- 
duced at Buenos Ayres in 1537, and so flourished 
in the wild state that in 1580 they were found as far 
south as the Strait of Magellan. Darwin was well 
fitted by the comprehensiveness of his observations 
to deal with the various factors of extinction and 
survival. He studied the species in their natural 
setting, the habitat, and range, and habits, and food 
of the different varieties. Traveling for three years 
and a half north and south on the continent of South 


America, he noticed one species replacing another, 
perhaps closely allied, species. Of the carrion-feed- 
ing hawks the condor has an immense range, but 
shows a predilection for perpendicular cliffs. If an 
animal die on the plain the polyborus has preroga- 
tive of feeding first, and is followed by the turkey 
buzzard and the gallinazo. European horses and cat- 
tle running wild in the Falkland Islands are some- 
what modified ; the horse as a species degenerating, 
the cattle increasing in size and tending to form 
varieties of different color. The soil being soft the 
hoofs of the horse grow long and produce lameness. 
Again, on the mainland, the niata, a breed of cattle 
supposed to have originated among the Indians south 
of the Plata, are, on account of the projection of the 
lower jaw, unable to browse as effectually as other 
breeds. This renders them liable to destruction in 
times of drought. A similar variation in structure 
had characterized a species of extinct ruminant in 

How disastrous a great drought might prove to 
the cattle of the Pampas is shown by the records of 
1825 and of 1830. So little rain feU that there was 
a complete failure of vegetation. The loss of cattle in 
one province alone was estimated at one million. Of 
one particular herd of twenty thousand not a single 
one survived. Darwin had many other instances of 
nature's devastations. After the Beagle sailed from 
the Plata, December 6, 1833, vast numbers of but- 
terflies were seen as far as the eye could range in 
bands of countless myriads. " Before sunset a strong 
breeze sprung up from the north, and this must have 
caused tens of thousands of the butterflies and other 


insects to perish." Two or three months before this 
he had ocular proof of the effect of a hailstorm, which 
in a very limited area killed twenty deer, fifteen 
ostriches, numbers of ducks, hawks, and partridges. 
In the war of extermination that was ever before 
the great naturalist's eye in South America, what is 
it that favors a species' survival or determines its 
extinction ? 

Not only is the struggle between the animals and 
inanimate nature, the plants and inanimate nature, 
plant and animal, rival animals, and rival plants ; it 
goes on between man and his environment, and, very 
fiercely, between man and man. Darwin was moved 
by intense indignation at the slavery on the east coast 
and the cruel oppression of the laborer on the west 
coast. He was in close contact with the sanguinary 
political struggles of South America, and with a war 
of attempted extermination against the Indian. He 
refers to the shocking but " unquestionable fact, that 
[in the latter struggle] all the women who appear 
above twenty years old are massacred in cold blood ! 
When I exclaimed that this appeared rather inhu- 
man, he [the informant] answered, 4 Why, what can 
be done ? they breed so ! ' 

In all his travels nothing that Darwin beheld 
made a deeper impression on his sensitive mind than 
primitive man. " Of individual objects, perhaps noth- 
ing is more certain to create astonishment than the 
first sight in his native haunt of a barbarian of 
man in his lowest and most savage state. One's mind 
hurries back over past centuries, and then asks, could 
our progenitors have been men like these ? ... I do 
not believe it is possible to describe or paint the dif- 


ference between savage and civilized man." It was 
at Tierra del Fuego that he was particularly shocked. 
He admired the Tahitians ; he pitied the natives of 
Tasmania, corralled like wild animals and forced to 
migrate ; he thought the black aborigines of Aus- 
tralia had been underestimated and remarked with 
regret that their numbers were decreasing through 
their association with civilized man, the introduc- 
tion of spirits, the increased difficulty of procuring 
food, and contact with European diseases. In this 
last cause tending to bring about extinction there 
was a mysterious element. In Chile his scientific 
acumen had been baffled in the attempt to explain the 
invasion of the strange and dreadful disease hydro- 
phobia. In Australia the problem of the transmission 
to the natives of various diseases, even by Europeans 
in apparent health, confronted his intelligence. " The 
varieties of man seem to act on each other in the same 
way as different specimens of animals the stronger 
always extirpating the weaker." 

It was at Wollaston Island, near Cape Horn, how- 
ever, that Darwin saw savage men held in extremity 
by the hard conditions of life, and at bay. They had 
neither food, nor shelter, nor clothing. They stood 
absolutely naked as the sleet fell on them and melted. 
At night, " naked and scarcely protected from the 
wind and rain of this tempestuous climate," they slept 
on the wet ground coiled up like animals. They sub- 
sisted on shell fish, putrid whale's blubber, or a few 
tasteless berries and fungi. At war, the different 
tribes are cannibals. Darwin writes, " It is certainly 
true, that when pressed in winter by hunger, they kill 
and devour their old women before they kill their 


dogs." A native boy, when asked by a traveler why 
they do this, had answered, " Doggies catch otters, 
old women no." In such hard conditions what are the 
characteristics that would determine the survival of 
individual or tribe ? One might be tempted to lay 
almost exclusive emphasis on physical strength, but 
Darwin was too wise ultimately to answer thus the 
question that for six or seven years was forming in 
his accurate and discriminating mind. 

On its way west in the Pacific the Beagle spent 
a month at the Galapagos Archipelago, which lies 
under the equator five or six hundred miles from the 
mainland. " Most of the organic productions are ab- 
original creations, found nowhere else ; there is even 
a difference between the inhabitants of the different 
islands ; yet all show a marked relationship with 
those of America." Why should the plants and ani- 
mals of the islands resemble those of the mainland, 
or the inhabitants of one island differ from those of 
a neighboring island ? Darwin had always held that 
species were created immutable, and that it was im- 
possible for one species to give rise to another. 

In the Galapagos Archipelago he found only one 
species of terrestrial mammal, a new species of mouse, 
and that only on the most easterly island of the group. 
On the South American continent there were at least 
forty species of mice, those east of the Andes being 
distinct from those on the west coast. Of land-birds 
he obtained twenty-six kinds, twenty-five of which 
were to be found nowhere else. Among these, a hawk 
seemed in structure intermediate between the buzzard 
and polyborus, as though it had been modified and 
induced to take over the functions of the South Ameri- 


can carrion-hawk. There were three species of mock- 
ing-thrush, two of them confined to one island each. 
There were thirteen species of finches, all peculiar to 
the archipelago. In the different species of geospiza 
there is a perfect gradation in the size of the beaks, 
only to be appreciated by seeing the specimens or 
their illustrations. 

Few of the birds were of brilliant coloration. 
The same was true of the plants and insects. Darwin 
looked in vain for one brilliant flower. This was in 
marked contrast to the fauna and flora of the South 
American tropics. The coloration of the species sug- 
gested comparison with that of the plants and animals 
of Patagonia. Amid brilliant tropical plants brilliant 
plumage may afford means of concealment, as well 
as being a factor in the securing of mates. 

Darwin found the reptiles the most striking fea- 
ture of the zoology of the islands. They seem to take 
the place of the herbivorous mammalia. The huge 
tortoise (Testudo nigra) native in the archipelago 
is so heavy as to be lifted only by six or eight men. 
(The young naturalist frequently got on the back of 
a tortoise, but as it moved forward under his encour- 
agement, he found it very difficult to keep his bal- 
ance.) Different varieties, if not species, characterize 
the different islands. Of the other reptilia should 
be noted two species of lizard of a genus {Ambly- 
rhynchus) confined to the Galapagos Islands. One, 
aquatic, a yard long, fifteen pounds in weight, with 
" limbs and strong claws admirably adapted for crawl- 
ing over the rugged and fissured masses of lava," 
feeds on seaweed. When frightened it instinctively 
shuns the water, as though it feared especially its 


aquatic enemies. The terrestrial species is confined to 
the central part of the group ; it is smaller than the 
aquatic species, and feeds on cactus, leaves of trees, 
and berries. 

Fifteen new species of sea-fish were obtained, dis- 
tributed in twelve genera. The archipelago, though 
not rich in insects, afforded several new genera, each 
island with its distinct kinds. The flora of the Gala- 
pagos Islands proved equally distinctive. More than 
half of the flowering plants are native, and the species 
of the different islands show wonderful differences. 
For example, of seventy-one species found on James 
Island thirty-eight are confined to the archipelago 
and thirty to this one island. 

In October the Beagle sailed west to Tahiti, New 
Zealand, Australia, Keeling or Cocos Islands, Mau- 
ritius, St. Helena, Ascension ; arrived at Bahia, Brazil, 
August 1, 1836 ; and finally proceeded from Brazil 
to England. Among his many observations, Darwin 
noted the peculiar animals of Australia, the kanga- 
roo-rat, and " several of the famous Ornithorhyri- 
chus paradoxus" or duckbill. On the Keeling or 
Cocos Islands the chief vegetable production is the 
cocoanut. Here Darwin observed crabs of monstrous 
size, with a structure which enabled them to open 
the cocoanuts. They thus secured their food, and 
accumulated "surprising quantities of the picked 
fibres of the cocoanut husk, on which they rest as a 

In preparing his Journal for publication in the 
autumn of 1836 the young naturalist saw how many 
facts pointed to the common descent of species. He 
thought that by collecting all facts that bore on the 


variation of plants and animals, wild or domesticated, 
light might be thrown on the whole subject. " I 
worked on true Baconian principles, and, without 
any theory, collected facts on a wholesale scale." He 
saw that pigeon-fanciers and stock-breeders develop 
certain types by preserving those variations that have 
the desired characteristics. This is a process of arti- 
ficial selection. How is selection made by Nature ? 

In 1838 he read Mai thus' Essay on the Prin- 
ciple of Population, which showed how great and 
rapid, without checks like war and disease, the in- 
crease in number of the human race would be. He 
had seen something in his travels of rivalry for 
the means of subsistence. He now perceived " that 
under these circumstances favorable variations would 
tend to be preserved, and unfavorable ones to be de- 
stroyed. The results of this would be the formation 
of a new species." As special breeds are developed by 
artificial selection, so new species evolve by a process 
of natural selection. Those genera survive which give 
rise to species adapted to new conditions of exist- 

In 1858, before Darwin had published his theory, 
he received from another great traveler, Alfred 
Russel Wallace, then at Ternate in the Moluccas, a 
manuscript essay, setting forth an almost identical 
view of the development of new species through the 
survival of the fittest in the struggle for existence. 



Charles Darwin, A Naturalist's Journal. 

Francis Darwin, The Life and Letters of Charles Darwin. 

W. A. Locy, Biology and its Makers (third revised edition), 

chap. xix. 

G. J. Romanes, Darwin and After Darwin, vol. I. 
A. R. Wallace, Darwinism. 
See also John W. Judd, The Coming of Evolution (The Cambridge 

Manuals of Science and Literature). 



IN the history of science war is no mere interruption, 
but a great stimulating influence, promoting directly 
or indirectly the liberties of the people, calling into 
play the energy of artisan and manufacturer, and in- 
creasing the demand for useful and practical studies. 
In the activities of naval and military equipment and 
organization this influence is obvious enough; it is 
no less real in the reaction from war which impels 
all to turn with new zest to the arts and industries 
of peace and to cherish whatever may tend to culture 
and civil progress. Not infrequently war gives rise, 
not only to new educational ideals, but to new insti- 
tutions and to new types of institution favorable 
to the advancement of science. As we have already 
seen, the Royal Society and Milton's Academies owed 
their origin to the Great Rebellion. Similarly the 
Ecole Polytechnique, mother of many scientific dis- 
coveries, rose in answer to the needs of the French 
Revolution. No less noteworthy was the reconstruction 
of education under the practical genius of Napoleon 
I, the division of France into academies, the found- 
ing of the lycees, the reestablishment of the great 
Ecole Normale, and the organization of the Imperial 
University with new science courses and new pro- 
vincial Faculties at Rennes, Lille, and elsewhere. 
With all these different forms in which the influence 
of war makes itself felt in the progress of science 


the life and career of Louis Pasteur (1822-1895), the 
founder of bacteriology, stood intimately associated. 

He was born, at Dole, but the family a few years 
later settled at Arbois. For three generations the 
Pasteurs had been tanners in the Jura, and they 
naturally adhered to that portion of the population 
which hailed the Revolution as a deliverance. The 
great-grandfather was the first freeman of Pasteur's 
forbears, having purchased with money his emanci- 
pation from serfdom. The father in 1811, at the age 
of twenty, was one of Napoleon's conscripts, and in 
1814 received from the Emperor, for valor and fidel- 
ity, the Cross of the Legion of Honor. The direct- 
ness and endurance of the influence of this trained 
veteran on his gifted son a hundred fine incidents 
attest. In 1848 year of revolt in the monarchies 
of Europe the young scientist enrolled himself in 
the National Guard, and, seeing one day in the Place 
du Pantheon a structure inscribed with the words 
autel de la patrie, he placed upon it all the humble 
means one hundred and fifty francs then at his 

It was in that same year that Pasteur put on 
record his discovery of the nature of racemic acid, 
his first great service to science, from which all his 
other services were to proceed. As a boy he had at- 
tended the college at Arbois where his teacher had in- 
spired him with an ambition to enter the great Ecole 
Normale. Before reaching that goal he took his bache- 
lor's degree in science as well as in arts at the Bes- 
ancon college. At Paris he came in contact with the 
leaders of the scientific world Claude Bernard, 
Balard, Dumas, Biot. 


J. B. Biot had entered the ranks of science by way 
of the Ecole Polytechnique and the artillery service. 
In 1819 he had announced that the plane of polar- 
ized light for example, a ray passed through Ice- 
land spar is deflected to right or left by various 
chemical substances. Among these is common tartaric 
acid the acid of grape-juice, obtained from wine 
lees. Racemic acid, however, which is identical with 
tartaric acid in its chemical constituents, is optically 
inactive, rotating the plane of polarized light neither 
to the right nor the left. This substance Pasteur 
subjected to special investigation. He scrutinized 
the crystals of sodium ammonium racemate obtained 
from aqueous solution. These he observed to be of 
two kinds differing in form as a right glove from a 
left, or as an object from its mirror-image. Separat- 
ing the crystals according to the difference of form, 
he made a solution from each group. One solution, 
tested in the polarized-light apparatus, turned the 
plane to the right ; the other solution turned it to the 
left. He had made a capital discovery of far-reaching 
importance, namely, that racemic acid is composite, 
consisting of dextro-tartaric and laBvo-tartaric acids. 
Biot hesitated to credit a mere tyro with such an 
achievement. The experiment was repeated in his 
presence. Convinced by ocular demonstration, he 
was almost overcome with emotion. " My dear boy,'* 
he exclaimed, "I have loved the sciences so much 
my life through that that makes my heart jump." 

Pasteur began his regular professional experience 
as a teacher of physics in the Dijon lycee, but he was 
soon transferred to the University of Strasburg 
(1849). There he married the daughter of the 


rector of the academic, and three years later became 
Professor of Chemistry. In 1854 he was appointed 
Dean of the Faculty of Sciences at Lille, a town 
then officially described as the richest center of in- 
dustrial activity in the north of France. In his open- 
ing address he showed the value and attractiveness 
of practical studies. He believed as an educator in 
the close alliance of laboratory and factory. Appli- 
cation should always be the aim, but resting on the 
severe and solid basis of scientific principles ; for it 
is theory alone which can bring forth and develop 
the spirit of invention. 

His own study of racemic acid, begun in the labo- 
ratories of Paris, and followed up in the factories of 
Leipzig, Prag, and Vienna, had led to his theory of 
molecular dissymmetry, the starting point of modern 
stereo-chemistry. It now gave rise on Pasteur's part 
to new studies and to new applications to the indus- 
tries. He tried an experiment which seems almost 
whimsical, placing ammonium racemate in the ordi- 
nary conditions of fermentation, and observed that 
only one part the dextro-rotatory ferments or 
putrefies. Why ? " Because the ferments of that fer- 
mentation feed more easily on the right hand than 
on the left hand molecules." He succeeded in keep- 
ing alive one of the commonest moulds on the sur- 
face of ashes and racemic acid, and saw the lasvo- 
tartaric acid appear. It was thus that he passed from 
the study of crystals to the study of ferments. 

In the middle of the nineteenth century little was 
known of the nature of fermentation, though some 
sought to explain by this ill-understood process the 
origin of various diseases and of putrefaction. Why 


does fruit-juice produce alcohol, wine turn to vin- 
egar, milk become sour, and butter rancid ? Pas- 
teur's interest in these problems of fermentation was 
stimulated by one of the industries of Lille. He was 
accustomed to visit with his students the factories of 
that place as well as those of neighboring French 
and Belgian cities. The father of one of his students 
was engaged in the manufacture of alcohol from beet- 
root sugar, and Pasteur came to be consulted when 
difficulties arose in the manufacturing process. He 
discovered a relationship between the development of 
the yeast and the success or failure of the fermenta- 
tion, the yeast globules as seen under the microscope 
showing an alteration of form when the fermentation 
was not proceeding satisfactorily. In 1857 Pasteur 
on the basis of this study was able to demonstrate 
that alcoholic fermentation, that is, the conversion 
of sugar into alcohol, carbonic acid, and other com- 
pounds, depends on the action of yeast, the cells of 
which are widely disseminated in the atmosphere. 

In this year of his second great triumph Pasteur 
was appointed director of science studies in the Ecole 
Normale, from which he had graduated in 1847. 
Two years later the loss of his daughter by a com- 
municable disease typhoid fever had a great 
effect on his sensitive and profound mind. Many of 
his opponents, it is true, found Pasteur implacable 
in controversy. Undoubtedly he had the courage of 
his convictions, and his belief that, for the sake of 
human welfare, right views his views won by tire- 
less experiment must prevail, gained him the name 
of a fighter. But in all the intimate relations of life 
his essential tenderness was manifest. Like Darwin 


he had a horror of inflicting pain, and always in- 
sisted, when operations on animals were necessary 
in the laboratory, on the use of anesthetics (our 
command of which had been greatly advanced by 
Simpson in 1847). Emile Roux said that Pasteur's 
agitation at witnessing the slightest exhibition of 
pain would have been ludicrous if, in so great a man, 
it had not been touching. 

A few months after his daughter's death Pasteur 
wrote to one of his friends : " I am pursuing as best 
I can these studies on fermentation, which are of 
great interest, connected as they are with the im- 
penetrable mystery of life and death. I am hoping 
to make a decisive advance very soon, by solving 
without the least lack of clearness the famous ques- 
tion of spontaneous generation." Two years previ- 
ously a scientist had claimed that animals and plants 
could be generated in a medium of artificial air or 
oxygen, from which all atmospheric air and all germs 
of organized bodies had been precluded. Pasteur 
now filtered atmospheric air through a plug of cot- 
ton or asbestos (a procedure which had been fol- 
lowed by others in 1854), and proved that in air 
thus treated no fermentation takes place. Nothing 
in the atmosphere causes life except the micro-organ- 
isms it contains. He even demonstrated that a pu- 
trescible fluid like blood will remain unchanged in 
an open vessel so constructed as to exclude atmos- 
pheric dust. 

Pasteur's critics maintained that if putrefaction 
and fermentation be caused solely by microscopic 
organisms, then these must be found everywhere and 
in such quantities as to encumber the air. He replied 


that they were less numerous in some parts of the 
atmosphere than in others. To prove his contention 
he set out for Arbois with a large number of glass 
bulbs each half filled with a putrescible liquid. The 
necks of the bulbs had been drawn out and hermet- 
ically sealed after the contents had been boiled. In 
case the necks were broken (to be again sealed im- 
mediately), the air would rush in, and (if it held 
the requisite micro-organisms) furnish the condi- 
tions for putrefaction. It was found that in every 
trial the contents of a certain number of the bulbs 
always escaped alteration. Twenty were opened in 
the country near Arbois free from human habita- 
tions. Eight out of the twenty showed signs of pu- 
trefaction. Twenty were exposed to the air on the 
heights of the Jura at an altitude of eight hundred 
and fifty meters above sea-level ; the contents of five 
of these subsequently putrefied. Twenty others were 
opened near Mont Blanc at an altitude of two thou- 
sand meters and while a wind was blowing from the 
Mer de Glace ; in this case the contents of only one 
of the bulbs became putrefied. 

While his opponents still professed to believe in 
the creation of organized beings lacking parents, 
Pasteur was under the influence of the theory of 
"the slow and progressive transformation of one 
species into another," and was becoming aware of 
phases of the struggle for existence hitherto shrouded 
in mystery. He wished he said to push these studies 
far enough to prepare the way for a serious investi- 
gation of the origin of disease. 

He returned to the study of lactic fermentation, 
showed that butyric fermentation may be caused by 


organisms which live in the absence of oxygen, while 
vinegar is produced from wine through the agency 
of bacteria freely supplied with the oxygen of the 
air. Pasteur was seeing ever more clearly the part 
played by the infinitesimally small in the economy 
of nature. Without these microscopic beings life 
would become impossible, because death would be 
incomplete. On the basis of Pasteur's study of fer- 
mentation, his demonstration that decomposition is 
owing to living organisms and that minute forms of 
life spring from parents like themselves, his disciple 
Joseph Lister began in 1864 to develop antiseptic 

Pasteur's attention was next directed to the wine 
industry, which then had an annual value to France 
of 500,000,000 francs. Might not the acidity, bit- 
terness, defective flavor, which were threatening the 
foreign sale of French wines, be owing to ferments ? 
He discovered that this was, indeed, the case, and 
that the diseases of wine could be cured by the sim- 
ple expedient of heating the liquor for a few mo- 
ments to a temperature of 50 to 60 C. Tests on a 
considerable scale were made by order of the naval 
authorities. The ship Jean Bart before starting on 
a voyage took on board five hundred liters of wine, 
half of which had been heated under Pasteur's direc- 
tions. At the end of ten months the pasteurized 
wine was mellow and of good color, while the wine 
which had not been heated had an astringent, almost 
bitter, taste. A more extensive test seven hundred 
hectoliters, of which six hundred and fifty had been 
pasteurized was carried out on the frigate la 
Sibylle with satisfactory results. Previously wines 


had been preserved by the addition of alcohol, which 
made them both dearer and more detrimental to 

In 1865 Pasteur was called upon to exercise his 
scientific acumen on behalf of the silk industry. A 
disease pebrine had appeared among silkworms 
in 1845. In 1849 the effect on the French industry 
was disastrous. In the single arrondissement of 
Alais an annual income of 120,000,000 francs was 
lost for the subsequent fifteen years. The mulberry 
plantations of the Cevennes were abandoned and the 
whole region was desolate. Pasteur, at the instiga- 
tion of the Minister of Agriculture, undertook an 
investigation. After four or five years, in spite of 
repeated domestic afflictions and the breakdown of 
his own health, he arrived at a successful conclu- 
sion. Pebrine, due to " corpuscles " readily detected 
under the microscope, could be recognized at the mo- 
ment of the moth's formation. A second disease, 
flacherie, was due to a micro-organism found in the 
digestive cavity of the moth. Measures were taken 
to select the seed of the healthy moths and to destroy 
the others. These investigations revealed the infini- 
tesimally small as disorganizers of living tissue, and 
brought Pasteur nearer his purpose " of arriving," 
as he had expressed it to Napoleon III in 1863, "at 
the knowledge of the causes of putrid and contagious 

Returning in July, 1870, from a visit to Liebig 
at Munich, Pasteur heard at Strasburg of the im- 
minence of war. All his dreams of conquest over 
disease and death seemed to vanish. He hurried to 
Paris. His son, eighteen years of age, set out with 


the army. Every student of the Ecole Normale en- 
listed. Pasteur's laboratory was used to house sol- 
diers. He himself wished to be enrolled in the Na- 
tional Guard, and had to be told that a half -paralyzed 
man could not render military service. He was ob- 
sessed with horror of wanton bloodshed and with 
indignation at the insolence of armed injustice. 
Trained to serve his country only in one way he 
tried, but in vain, to resume his researches. He re- 
tired to the old home town of Arbois, and sought to 
distract his mind from the contemplation of human 
baseness. Arbois was entered by the enemy in Janu- 
ary with the usual atrocities of war. Pasteur accom- 
panied by wife and daughter had gone in search of his 
son, sick at Pontarlier. The boy was restored to health 
and returned to his regiment the following month. 

During this crisis Pasteur and his friends felt, as 
many English scientists feel in 1917, in reference 
to ignorance in high places. " We are paying the 
penalty," he said, " of fifty years' forgetf ulness of 
science, and of its conditions of development." Again 
he speaks, as Englishmen to-day very well might, of 
the neglect, disdain even, of the country for great 
intellectual men, especially in the realm of exact sci- 
ence. In the same strain his friend Bertin said that 
after the war everything would have to be rebuilt 
from the top to the bottom, the top especially. Pas- 
tenr recalled the period of 1792 when Lavoisier, 
Berthollet, Monge, Fourcroy, Guyton de Morveau, 
Chaptal, Clouet, and other scientists had furnished 
France with gunpowder, steel, cannon, fortifications, 
balloons, leather, and other means to repel unjust 


On the day after Sedan the Quaker surgeon Lister 
had published directions for the use of aqueous solu- 
tions of carbolic acid to destroy septic particles in 
wounds, and of oily solutions "to prevent putrefac- 
tive fermentation from without." He recognized that 
the earlier the case comes from the field the greater 
the prospect of success. Sedillot (the originator 
of the term " microbe"), at the head of an* ambulance 
corps in Alsace, was a pioneer in the rapid transport 
of wounded from the field of battle. He knew the 
horrors of purulent infection in military hospitals, 
and regretted that the principles of Pasteur and 
Lister were not more fully applied. 

After the war was over, Pasteur kept repeating 
his life-long exhortation : We must work " Tra- 
vaillez, travaillez toujours ! ' He applied himself to 
a study of the brewing industry. He did not believe 
in spontaneous alterations, but found that every 
marked change in the quality of beer coincides 
with the development of micro-organisms. ' He was 
able to tell the English brewers the defects in their 
output by a microscopic examination of their yeast. 
(" W r e must make some friends for our beloved 
France," he said.) Bottled beer could be pasteur- 
ized by bringing it to a temperature of 50 to 55 C. 
Whenever beer contains no ferments it is unaltera- 
ble. His scrupulous mind was coming ever closer to 
the goal of his ambition. This study of the diseases 
of beer led him nearer to a knowledge of infections. 
Many micro-organisms may, must, be detrimental to 
the health of man and animals. 

In 1874 the Government conferred upon Pasteur 
a life annuity of twelve thousand francs, an equiva- 


lent of his salary as Professor of Chemistry at the 
Sorbonne. (He had received appointment in 1867, 
but had been compelled by ill-health to relinquish 
his academic functions.) The grant was in all re- 
spects wise. Huxley remarked that Pasteur's discov- 
eries alone would suffice to cover the war indemnity 
of five milliards paid by France to Germany in 1871. 
Moreover, all his activities were dictated by patriotic 
motives. He felt that science is of no country and 
that its conquests belong to mankind, but that the 
scientist must be a patriot in the service of his native 

Pasteur now applied his energies to the study of 
virulent diseases, following the principles of his ear- 
lier investigations. He opposed those physicians who 
believed in the spontaneity of disease, and he wished 
to wage a war of extermination against all injurious 
organisms. As early as 1850 Davaine and Rayer had 
shown that a rod-like micro-organism was always pres- 
ent in the blood of animals dying of anthrax, a dis- 
ease which was destroying the flocks and herds of 
France. Dr. Koch, who had served in the Franco- 
Prussian War, succeeded in 1876 in obtaining pure 
cultures of this bacillus and in defining its relation 
to the disease. Pasteur took up the study of anthrax 
in 1877, verified previous discoveries, and, as we shall 
see, sought means for the prevention of this pest. 
He discovered (with Joubert and Chamberland) the 
bacillus of malignant edema. He applied the prin- 
ciples of bacteriology to the treatment of puerperal 
fever, which in 1864 had rendered fatal 310 cases 
out of 1350 confinements in the Maternite in Paris. 
Here he had to fight against conservatism in the 


medical profession, and he fought strenuously, one of 
his disciples remarking that it is characteristic of lofty 
minds to put passion into ideas. Swine plague, which 
in the United States in 1879 destroyed over a mil- 
lion hogs, and chicken cholera, also engaged his at- 

Cultures of chicken cholera virus kept for some 
time became less active. A hen that chanced to be 
inoculated with the weakened virus developed the 
disease, but, after a time, recovered (much as patients 
after the old-time smallpox inoculations). It was then 
inoculated with a fresh culture supposed sufficient 
to cause death. It again recovered. The use of the 
weakened inoculation had developed its resistance to 
infection. A weakened virus recovered its strength 
when passed through a number of sparrows, the sec- 
ond being inoculated with virus from the first, the 
third from the second, and so on (this species being 
subject to the disease) . Hens that had not had chicken 
cholera could be rendered immune by a series of at- 
tenuated inoculations gradually increasing in strength. 
In the case of anthrax the virus could be weakened 
by keeping it at a certain temperature, while it could 
be strengthened by passage through a succession of 
guinea-pigs. There are of course many instances 
where pathogenic bacteria lose virulence in passing 
from one animal to another, the human smallpox 
virus, for example, producing typical cowpox in an 
inoculated heifer. These facts help to explain why 
certain infections have grown less virulent in the 
course of history, and why infections of which civil- 
ized man has become tolerant prove fatal when im- 
parted to the primitive peoples of Australia. 


Pasteur's preventive inoculation for anthrax was 
tested under dramatic circumstances at Melun in 
June, 1881. Sixty sheep and a number of cows were 
subjected to experiment. None of the sheep that had 
been given the preventive treatment died from the 
crucial inoculation ; while all those succumbed which 
had not received previous treatment. The test for the 
cows was likewise successful. Pasteur thought that 
in places where sheep dead of anthrax had been buried, 
the microbes were brought to the surface in the cast- 
ings of earthworms. Hence he issued certain direc- 
tions to prevent the transmission of the disease. He 
also aided agriculture by discovering a vaccine for 
swine plague. 

When Pasteur at the age of fifteen was in Paris, 
overcome with homesickness, he had exclaimed, "If 
I could only get a whiff of the old tannery yard, 
I feel I should be cured." Certainly every time he 
came in contact with the industries silk, wine, beer, 
wool his scientific insight, Antaeus-like, seemed to 
revive. All his life he had preached the doctrine of 
interchange of service between theory and practice, 
science and the occupations. What he did is more 
eloquent than words. His theory of molecular dis- 
symmetry, that the atoms in a molecule may be ar- 
ranged in left-hand and right-hand spirals or other 
tridimensional figures corresponding to asymmetrical 
crystals, touches the abstruse question of the consti- 
tution of matter. His preventive treatment breathes 
new life into the old dictum similia similibus cu- 
rantur. The view he adopted of the gradual trans- 
formation of species offers a new interpretation of the 
speculations of philosophy in reference to being and 


becoming and the relation of the real to the concrete. 
Yet Pasteur felt he could learn much of value from 
the simplest shepherd or vine-dresser. 

He was complete in the simplicity of his affec- 
tions, in his compassion for all suffering, in the 
warmth of his religious faith, and in his devotion to 
his country. He thought France was to regain her 
place in the world's esteem through scientific prog- 
ress. He was therefore especially gratified in Au- 
gust, 1881, at the thunders of applause which 
greeted his appearance at the International Medical 
Congress in London. There he was introduced to 
the Prince of Wales (fondateur de V Entente Cor- 
diale), " to whom I bowed, saying that I was 
happy to salute a friend of France." 

Pasteur's investigation of rabies began in this 
same year. Difficulty was found in isolating the 
microbe of the rabic virus, but an inoculation from 
the medulla oblongata of a mad dog injected into 
one of the brain membranes (dura mater) of an- 
other dog invariably brought on the symptoms of 
rabies. To obtain attenuation of the virus it was 
sufficient to dry the medulla taken from an infected 
rabbit. The weakened virus increased in strength 
when cultivated in a series of rabbits. Pasteur ob- 
tained in inoculations of graded virulence, which 
could be administered hypodermically, a means of 
prophylaxis after bites. He conjectured that in vac- 
cinal immunity the virus is accompanied by a sub- 
stance which makes the nervous tissue unfavorable 
for the development of the microbe. 

It was not till 1885 that he ventured to use his 
discovery to prevent hydrophobia. On July 6 a little 


boy, Joseph Meister, from a small place in Alsace 
was brought by his mother to Paris for treatment. 
He had been severely bitten by a mad dog. Pasteur, 
with great trepidation, but moved by his usual com- 
passion, undertook the case. The inoculations of 
the attenuated virus began at once. The boy suf- 
fered little inconvenience, playing about the labo- 
ratory during the ten days the treatment lasted. 
Pasteur was racked with fears alternating with 
hopes, his anxiety growing more intense as the viru- 
lence of the inoculations increased. On August 20, 
however, even he was convinced that the treatment 
was a complete success. In October a shepherd lad, 
who, though badly bitten himself, had saved some 
other children from the attack of a rabid dog, was 
the second one to benefit by the great discovery. 
Pasteur's exchange of letters with these boys after 
they had returned to their homes reveals the kindli- 
ness of his disposition. His sentiment toward chil- 
dren had regard both to what they were and to what 
they might become. One patient, brought to him 
thirty-seven days after being bitten, he failed to 
save. By March 1 Pasteur reported that three hun- 
dred and fifty cases had been treated with only one 

When subscriptions were opened for the erection 
and endowment of the Pasteur Institute, a sum of 
2,586,680 francs was received in contributions from 
many different parts of the world. Noteworthy 
among the contributors were the Emperor of Brazil, 
the Czar of Russia, the Sultan of Turkey, and the 
peasants of Alsace. On November 14, 1888, Presi- 
dent Carnot opened the institution, which was soon 


to witness the triumphs of Roux, Yersin, Metchni- 
koff, and other disciples of Pasteur. In the address 
prepared for this occasion the veteran scientist 
wrote : 

" If I might be allowed, M. le President, to con- 
clude by a philosophical remark, inspired by your 
presence in this home of work, I should say that 
two contrary laws seem to be wrestling with each 
other at the present time; the one a law of blood 
and death, ever devising new means of destruc- 
tion and forcing nations to be constantly ready for 
the battlefield the other, a law of peace, work, 
and health, ever developing new means of delivering 
man from the scourges which beset him. 

" The one seeks violent conquests, the other the 
relief of humanity. The latter places one human life 
above any victory; while the former would sacrifice 
hundreds and thousands of lives to the ambition of 
one. The law of which we are the instruments 
seeks, even in the midst of carnage, to cure the san- 
guinary ills of the law of war ; the treatment in- 
spired by our antiseptic methods may preserve thou- 
sands of soldiers. Which of these two laws will 
ultimately prevail God alone knows. But we may 
assert that French science will have tried, by obey- 
ing the law of humanity, to extend the frontiers of 



W. W. Ford, The Life and Work of Robert Koch, Bulletin of the 
Johns Hopkins Hospital, Dec. 1911, vol. 22. 

C. A. Herter, The Influence of Pasteur on Medical Science, Bul- 
letin of the Johns Hopkins Hospital, Dec. 1903, vol. 14. 

E. O. Jordan, General Bacteriology (fourth edition, 1915). 

Charles C. W. Judd, The Life and Work of Lister, Bulletin of 
the Johns Hopkins Hospital, Oct. 1910, vol. 21. 

Stephen Paget, Pasteur and After Pasteur. 

W. T. Sedgwick, Principles of Sanitary Science. 

Rene Vallery-Radot, Life of Pasteur. 




IN his laudation of the nineteenth century Alfred 
Russel Wallace ventured to enumerate the chief in- 
ventions of that period: (1) Railways; (2) steam 
navigation; (3) electric telegraphs; (4) the tele- 
phone; (5) friction matches; (6) gas-lighting; 
(7) electric-lighting; (8) photography; (9) the 
phonograph; (10) electric transmission of power; 
(11) Rontgen rays; (12) spectrum analysis; (13) 
anaesthetics; (14) antiseptic surgery. All preced- 
ing centuries less glorious than the nineteenth 
can claim but seven or eight capital inventions : 
(1) Alphabetic writing; (2) Arabic numerals; (3) 
the mariner's compass; (4) printing; (5) the tele- 
scope; (6) the barometer and thermometer; (7) the 
steam engine. Similarly, to the nineteenth century 
thirteen important theoretical discoveries are as- 
cribed, to the eighteenth only two, and to the 
seventeenth five. 

Of course the very purpose of these lists namely, 
to compare the achievements of one century with 
those of other centuries inclines us to view each 
invention as an isolated phenomenon, disregard- 
ing its antecedents and its relation to contempo- 
rary inventions. Studied in its development, steam 
navigation is but an application of one kind of 
steam engine, and, moreover, must be viewed as a 


phase in the evolution of navigation since the earli- 
est times. Like considerations would apply to rail- 
ways, antiseptic surgery, or friction matches. The 
nineteenth-century inventor of the friction match 
was certainly no more ingenious (considering the 
means that chemistry had put at his disposal) 
than many of the savages who contributed by their 
intelligence to methods of producing, maintaining, 
and using fire. In fact, as we approach the consid- 
eration of prehistoric times it becomes difficult to 
distinguish inventions from the slow results of de- 
velopment in metallurgy, tool-making, building, 
pottery, war-gear, weaving, cooking, the domestica- 
tion of animals, the selection and cultivation of 
plants. Moreover, it is scarcely in the category of 
invention that the acquisition of alphabetic writing 
or the use of Arabic numerals properly belongs. 

These and other objections, such as the omission 
of explosives, firearms, paper, will readily occur to 
the reader. Nevertheless, these lists, placed side by 
side with the record of theoretic discoveries, en- 
courage the belief that, more and more, sound theory 
is productive of useful inventions, and that hence- 
forth it must fall to scientific endeavor rather than 
to lucky accident to strengthen man's control over 
Nature. Even as late as the middle of the nineteenth 
century accident and not science was regarded as 
the fountain-head of invention, and the view that a 
knowledge of the causes and secret motions of things 
would lead to "the enlarging of the bounds of hu- 
man empire to the effecting of all things possible v 
was scouted as the idle dream of a doctrinaire. 

In the year 1896 three important advances were 


made in man's mastery of his environment. These 
are associated with the names of Marconi, Becquerel, 
and Langley. It was in this year that the last-named, 
long known to the scientific world for his discoveries 
in solar physics, demonstrated in the judgment of 
competent witnesses the practicability of mechanical 
flight. This was the result of nine years' experimen- 
tation. It was followed by several more years of 
fruitful investigation, leading to that ultimate tri- 
umph which it was given to Samuel Pierpont Lang- 
ley to see only with the eye of faith. 

The English language has need of a new word 
(" plane ") to signify the floating of a bird upon the 
wing with slight, or no, apparent motion of the 
wings ( planer, schweberi). To hover has other con- 
notations, while to soar is properly to fly upward, 
and not to hang poised upon the air. The miracle of 
a bird's flight, that steady and almost effortless mo- 
tion, had interested Langley intensely as had also 
the sun's radiation from the years of his childhood. 
The phenomenon (the way of an eagle in the air) 
has always, indeed, fascinated the human imagina- 
tion and at the same time baffled the comprehension. 
The skater on smooth ice, the ship riding at sea, 
or even the fish floating in water, offers only an 
incomplete analogy ; for the fish has approximately 
the same weight as the water it displaces, while a 
turkey buzzard of two or three pounds' weight will 
circle by the half-hour on motionless wing upheld 
only by the thin medium of the air. 

In 1887, prior to his removal to Washington as 
Secretary of the Smithsonian Institution, Langley 
began his experiments in aerodynamics at the old 


observatory in Allegheny now a part of the city 
of Pittsburgh. His chief apparatus was a whirling 
table, sixty feet in diameter, and with an outside 
speed of seventy miles an hour. This was at first 
driven by a gas engine, ironically named " Auto- 
matic," for which a steam engine was substituted 
in the following year. By means of the whirling 
table and a resistance-gauge (dynamometer chrono- 
graph) Langley studied the effect of the air on 
planes of varying lengths and breadths, set at vary- 
ing angles, and borne horizontally at different veloc- 
ities. At times he substituted stuffed birds for the 
metal planes, on the action of which under air pres- 
sure his scientific deductions were based. In 1891 he 
published the results of his experiments. These proved 
in opposition to the teaching of some very distin- 
guished scientists that the force required to sustain 
inclined planes in horizontal locomotion through the 
air diminishes with increased velocity (at least within 
the limits of the experiment). Here a marked con- 
trast is shown between aerial locomotion on the one 
hand, and land and water locomotion on the other ; 
" whereas in land or marine transport increased speed 
is maintained only by a disproportionate expenditure 
of power, within the limits of experiment in such 
aerial horizontal transport, the, higher speeds are 
more economical of power than the lower ones." 
Again, the experiments demonstrated that the force 
necessary to maintain at high velocity an apparatus 
consisting of planes and motors could be produced 
by means already available. It was found, for ex- 
ample, that one horse-power rightly applied is suffi- 
cient to maintain a plane of two hundred pounds in 


horizontal flight at a rate of about forty-five miles an 
hour. Langley had in fact furnished experimental 
proof that the aerial locomotion of bodies many times 
heavier than air was possible. He reserved for fur- 
ther experimentation the question of aerodromics, the 
form, ascent, maintenance in horizontal position, and 
descent of an aerodrome (aepoSpd/jios, traversing the 
air), as he called the prospective flying machine. He 
believed, however, that the time had come for seriously 
considering these things, and intelligent physicists, 
who before the publication of Langley 's experiments 
had regarded all plans of aerial navigation as uto- 
pian, soon came to share his belief. According to Oc- 
tave Chanute there was in Europe in 1889 utter 
disagreement and confusion in reference to fun- 
damental questions of aerodynamics. He thought 
Langley had given firm ground to stand upon con- 
cerning air resistances and reactions, and that the 
beginning of the solution of the problem of aerial 
navigation would date from the American scientist's 
experiments in aerodynamics. 

Very early in his investigations Langley thought 
he received through watching the anemometer a clue 
to the mystery of flight. Observations, begun at Pitts- 
burgh in 1887 and continued at Washington in 1893, 
convinced him that the course of the wind is " a se- 
ries of complex and little-known phenomena," and 
that a wind to which we may assign a mean velocity 
of twenty or thirty miles an hour, even disregarding 
the question of strata and currents, is far from being 
a mere mass movement, and consists of pulsations 
varying both in rate and direction from second to sec- 
ond. If this complexity is revealed by the stationary 


anemometer which may register a momentary calm 
in the midst of a gale how great a diversity of 
pressure must exist in a large extent of atmosphere. 
This internal work of the wind will lift the soaring 
bird at times to higher levels, from which without 
special movement of the wings it may descend in 
the very face of the wind's general course. 

From the beginning, however, of his experiments 
Langley had sought to devise a successful flying 
machine. In 1887 and the following years he con- 
structed about forty rubber-driven models, all of 
which were submitted to trial and modification. 
From these tests he felt that he learned much about 
the conditions of flight in free air which could not 
be learned from the more definitely controlled tests 
with simple planes on the whirling table. His essen- 
tial object was, of course, to reduce the principles of 
equilibrium to practice. Besides different forms and 
sizes he tried various materials of construction, and 
ultimately various means of propulsion. Before he 
could test his larger steam-driven models, made for 
the most part of steel and weighing about one thou- 
sand times as much as the air displaced, Langley 
spent many months contriving and constructing 
suitable launching apparatus. The solution of the 
problem of safe descent after flight he in a sense 
postponed, conducting his experiments from a house- 
boat on the Potomac, where the model might come 
down without serious damage. 

It was on May 6, 1896 (the anniversary of which 
date is now celebrated as Langley Day), that the 
success was achieved which all who witnessed it con- 
sidered decisive of the future of mechanical flight. 


A photograph taken at the moment of launching Langley's aerodrome 

May 6, 1896 


The whole apparatus steel frame, miniature steam 
engine, smoke stack, condensed-air chamber, gaso- 
line tank, wooden propellers, wings weighed about 
twenty-four pounds. There was developed a steam 
pressure of about 115 pounds, and the actual power 
was nearly one horse-power. At a given signal the 
aeroplane was released from the overhead launching 
apparatus on the upper deck of the house-boat. It 
rose steadily to an ultimate height of from seventy 
to a hundred feet. It circled (owing to the guys of 
one wing being loose) to the right, completing two 
circles and beginning a third as it advanced ; so that 
the whole course had the form of a spiral. At the 
end of one minute and twenty seconds the propellers 
began to slow down owing to the exhaustion of fuel. 
The aeroplane descended slowly and gracefully, ap- 
pearing to settle on the water. It seemed to Alex- 
ander Graham Bell that no one could witness this 
interesting spectacle, of a flying machine in perfect 
equilibrium, without being convinced that the possi- 
bility of aerial flight by mechanical means had been 
demonstrated. On the very day of the test he wrote 
to the Academic des Sciences that there had never 
before been constructed, so far as he knew, a heavier- 
than-air flying machine, or aerodrome, which could 
by its own power maintain itself in the air for more 
than a few seconds. 

Langley felt that he had now completed the work 
in this field which properly belonged to him as a 
scientist " the demonstration of the practicability 
of mechanical flight " and that the public might 
look to others for its development and commercial 
exploitation. Like Franklin and Davy he declined 


to take out patents, or in any way to make money 
from scientific discovery; and like Henry, the first 
Secretary of the Smithsonian Institution (to whom 
the early development of electro-magnetic machines 
was due), he preferred to be known as a scientist 
rather than as an inventor. 

Nevertheless, Langley's desire to construct a large, 
man-carrying aeroplane ultimately became irresist- 
ible. Just before the outbreak of the Spanish War 
in 1898 he felt that such a machine might be of 
service to his country in the event of hostilities that 
seemed to him imminent. The attention of President 
McKinley was called to the matter, and a joint com- 
mission of Army and Navy officers was appointed to 
make investigation of the results of Professor Lang- 
ley's experiments in aerial navigation. A favorable 
report having been made by that body, the Board of 
Ordnance and Fortification recommended a grant of 
fifty thousand dollars to defray the expenses of fur- 
ther research. Langley was requested to undertake 
the construction of a machine which might lead to 
the development of an engine of war, and in Decem- 
ber, 1898, he formally agreed to go on with the work. 

He hoped at first to obtain from manufacturers 
a gasoline engine sufficiently light and sufficiently 
powerful for a man-carrying machine. After several 
disappointments, the automobile industry being then 
in its infancy, he succeeded in constructing a five- 
cylinder gasoline motor of fifty-two horse-power and 
weighing only about a hundred and twenty pounds. 
He also constructed new launching apparatus. After 
tests with superposed sustaining surfaces, he adhered 
to the "single-tier plan." There is interesting evi- 


dence that in 1900 Langley renewed his study of the 
flight of soaring birds, the area of their extended 
wing surface in relation to weight, and the vertical 
distance between the center of pressure and the cen- 
ter of gravity in gulls and different species of buz- 
zards. He noted among other things that the tilting 
of a wing was sufficient to bring about a complete 
change of direction. 

By the summer of 1903 two new machines were 
ready for field trials, which were undertaken from a 
large house-boat, especially constructed for the pur- 
pose and then moored in the mid-stream of the 
Potomac about forty miles below Washington. The 
larger of these two machines weighed seven hundred 
and five pounds and was designed to carry an en- 
gineer to control the motor and direct the flight. 
The motive power was supplied by the light and 
powerful gasoline engine already referred to. The 
smaller aeroplane was a quarter-size model of the 
larger one. It weighed fifty-eight pounds, had an en- 
gine of between two and a half and three horse-power, 
and a sustaining surface of sixty-six square feet. 

This smaller machine was tested August 8, 1903, 
the same launching apparatus being employed as 
with the steam-driven models of 1896. In spite of 
the fact that one of the mechanics failed to withdraw 
a certain pin at the moment of launching, and that 
some breakage of the apparatus consequently oc- 
curred, the aeroplane made a good start, and fulfilled 
the main purpose of the test by maintaining a per- 
fect equilibrium. After moving about three hundred 
and fifty feet in a straight course it wheeled a quar- 
ter-circle to the right, at the same time descending 


slightly, the engine slowing down. Then it began to 
rise, moving straight ahead again for three or four 
hundred feet, the propellers picking up their former 
rate. Once more the engine slackened, but, before 
the aeroplane reached the water, seemed to regain 
its normal speed. For a third time the engine slowed 
down, and, before it recovered, the aeroplane had 
touched the water. It had traversed a distance of 
one thousand feet in twenty-seven seconds. One of 
the workmen confessed that he had poured into the 
tank too much gasoline. This had caused an overflow 
into the intake pipe, which in turn interfered with 
the action of a valve. 

The larger aeroplane with the engineer Manly on 
board was first tested on October 7 of the same year, 
but the front guy post caught in the launching car 
and the machine plunged into the water a few feet 
from the house-boat. In spite of this discouraging 
mishap the engineers and others present felt confi- 
dence in the aeroplane's power to fly. What would 
to-day be regarded by an aeronaut as a slight set- 
back seemed at that moment like a tragic failure. 
The fifty thousand dollars had been exhausted nearly 
two years previously ; Professor Langley had made 
as full use as seemed to him advisable of the resources 
put at his disposal by the Smithsonian Institution ; 
the young men of the press, for whom the supposed 
aberration of a great scientist furnished excellent 
copy, were virulent in their criticisms. Manly made 
one more heroic attempt under very unfavorable con- 
ditions at the close of a winter's day (December 8, 
1903). Again difficulty occurred with the launching 
gear, the rear wings and rudder being wrecked be- 


fore the aeroplane was clear of the ways. The exper- 
iments were now definitely abandoned, and the in- 
ventor was overwhelmed by the sense of failure, and 
still more by the skepticism with which the public 
had regarded his endeavors. 

In 1905 an account of Langley's aeroplane ap- 
peared in the Bulletin of the Italian Aeronautical 
Society. Two years later this same publication in 
an article on a new Ble'riot aeroplane said : " The 
Ble'riot IV in the form of a bird . . . does not ap- 
pear to give good results, perhaps on account of the 
lack of stability, and Ble'riot, instead of trying some 
new modification which might remedy such a grave 
fault, laid it aside and at once began the construc- 
tion of a new type, No. V, adopting purely and sim- 
ply the arrangement of the American, Langley, which 
offers a good stability." In the summer of 1907 
Ble'riot obtained striking results with this machine, 
the launching problem having been solved in the 
previous year the year of Langley's death by 
the use of wheels which permitted the aeroplane to 
get under way by running along the ground under 
its own driving power. The early flights with No. V 
were made at a few feet from the ground, and the 
clever French aviator could affect the direction of 
the machine by slightly shifting his position, and 
even had skill to bring it down by simply leaning 
forward. By the use of the steering apparatus he 
circled to the right or to the left with the grace of 
a bird on the wing. When, on July 25, 1909, Ble'riot 
crossed the English Channel in his monoplane, all 
the world knew that man's conquest of the air was a 
fait accompli. 


About three years after Langley's death the Board of 
Regents of the Smithsonian Institution established the 
Langley Medal for investigations in aerodromics in its 
application to aviation. The first award went (1909) 
to Wilbur and Orville Wright, the second (1913) 
to Mr. Glenn H. Curtiss and M. Gustave Eiffel. On 
the occasion of the presentation of the medals of the 
second award May 6, 1913 the Langley Me- 
morial Tablet, erected in the main vestibule of the 
Smithsonian building, was unveiled by the scientist's 
old friend, Dr. John A. Brashear. In the words of 
the present Secretary of the Institution, the tablet 
represents Mr. Langley seated on a terrace where 
he has a clear view of the heavens, and, in a medita- 
tive mood, is observing the flight of birds, while in 
his mind he sees his aerodrome soaring above them. 

The lettering of the tablet is as follows : 








'*! have brought to a close the portion of the 
work which seemed to be especially mine, the 
demonstration of the practicability of mechan- 
ical flight.'* 

" The great universal highway overhead is now 
soon to be opened." Langley, 1897. 


A still more fitting tribute to the memory of the 
great inventor came two years later from a success- 
ful aviator. In the spring of 1914 Mr. Glenn H. 
Curtiss was invited to send apparatus to Washing- 
ton for the Langley Day Celebration. He expressed 
the desire to put the Langley aeroplane itself in the 
air. The machine was taken to the Curtiss Aviation 
Field at Keuka Lake, New York. Langley's method 
of launching had been proved practical, but Curtiss 
finally decided to start from the water, and accord- 
ingly fitted the aeroplane with hydroaeroplane floats. 
In spite of the great increase in weight involved by 
this addition, the Langley aeroplane, under its own 
power plant, skimmed over the wavelets, rose from 
the lake, and soared gracefully in the air, maintain- 
ing its equilibrium, on May 28, 1914, over eight 
years after the death of its designer. When furnished 
with an eighty horse-power motor, more suited to its 
increased weight, the aerodrome planed easily over the 
water in more prolonged flight. In the periodical 
publications of June, 1914, may be read the eloquent 
announcement : " Langley's Folly Flies." 



Alexander Graham Bell, Experiments in Mechanical Flight, 
Nature, May 28, 1896. 

Alexander Graham Bell, The Pioneer Aerial Flight, Scientific 
American, Supplement, Feb. 26, 1910. 

S. P. Langley, Experiments in Aerodynamics. 

S. P. Langley, The "Flying Machine," McClure's, June, 1897 
(illustrated) . 

Langley Memoir on Mechanical Flight, Smithsonian Contributions 
to Knowledge, vol. 27, no. 3 (illustrated). 

Scientific American, Jan. 13, 1912, A Memorial Honor to a 
Pioneer Inventor. 

The Smithsonian Institution 1846-1896. The History of its First 
Half-Century, edited by G. B. Goode. 

A. F. Zahm, The First Man-carrying Aeroplane capable of Sus- 
tained Free Flight, Annual Report of the Smithsonian Insti- 
tution, 1914 (illustrated). 




THE untrained mind, reliant on so-called facts and 
distrustful of mere theory, inclines to think of truth 
as fixed rather than progressive, static rather than 
dynamic. It longs for certainty and repose, and has 
little patience for any authority that does not claim 
absolute infallibility. Many a man of the world is 
bewildered to find Newton's disciples building upon 
or refuting the teachings of the master, or to learn 
that Darwin's doctrine is itself subject to the univer- 
sal law of change and development. Though in ethics 
and religion the older order changes yielding place to 
new, and the dispensation of an eye for an eye and 
a tooth for a tooth finds its fulfilment and culmina- 
tion in a dispensation of forbearance and non-resist- 
ance of evil, still many look upon the overthrow of 
any scientific theory not as a sign of vitality and ad- 
vance, but as a symptom of the early dissolution or 
at least of the bankruptcy of science. It is not sur- 
prising, therefore, that the public regard the scientific 
hypothesis with a kind of contempt ; for a hypothesis 
(u7ro'#e<m, foundation, supposition) is necessarily 
ephemeral. When disproved, it is shown to have been 
a false supposition; when proved, it is no longer 

Yet a page from the history of science should in- 
dicate that hypotheses play a role in experimental 


science and lead to results that no devotee of facts 
and scorner of mere theory can well ignore. 

In 1895 Sir William Ramsay, who in the previous 
year had discovered an inert gas, argon, in the at- 
mosphere, identified a second inert gas (obtained 
from minerals containing uranium and thorium) as 
helium (^fXto?, sun), an element previously revealed 
by spectrum analysis as a constituent of the sun. In 
the same year Rontgen, while experimenting with the 
rays that stream from the cathode in a vacuum tube, 
discovered new rays (which he called X-rays) pos- 
sessed of wonderful photographic power. At the be- 
ginning of 1896 Henri Becquerel, experimenting on 
the supposition, or hypothesis, that the emission of 
rays was associated with phosphorescence, tested the 
photographic effects of a number of phosphorescent 
substances. He exposed, among other compounds, 
crystals of the double sulphate of uranium and po- 
tassium to sunlight and then placed upon the crystals 
a photographic plate wrapped in two thicknesses of 
heavy black paper. The outline of the phosphorescent 
substance was developed on the plate. An image of a 
coin was obtained by placing it between uranic salts 
and a photographic plate. Two or three days after 
reporting this result Becquerel chanced (the sunlight 
at the time seeming to him too intermittent for ex- 
perimentation) to put away in the same drawer, and in 
juxtaposition, a photographic plate and these phos- 
phorescent salts. To his surprise he obtained a clear 
image when the plate w r as developed. He now assumed 
the existence of invisible rays similar to X-rays. 
They proved capable of passing through sheets of 
aluminum and of copper, and of discharging electri- 


fied bodies. Days elapsed without any apparent dimi- 
nution of the radiation. On the supposition that the 
rays might resemble light he tried to refract, reflect, 
and polarize them ; but this hypothesis was by the ex- 
periments of Rutherford, and of Becquerel himself, 
ultimately overthrown. In the mean time the French 
scientist obtained radiations from metallic uranium 
and from uranous salts. These, in contrast with 
the uranic salts, are non-phosphorescent. Becquerel's 
original hypothesis was thus overthrown. Radiation 
is a property inherent in uranium and independent 
both of light and of phosphorescence. 

On April 13 and April 23 (1898) respectively 
Mme. Sklodowska Curie and G. C. Schmidt pub- 
lished the results of their studies of the radiations 
of the salts of thorium. Each of these studies was 
based on the work of Becquerel. Mme. Curie ex- 
amined at the same time the salts of uranium and a 
number of uranium ores. Among the latter she 
made use of the composite mineral pitchblende from 
the mines of Joachiinsthal and elsewhere, and found 
that the radiations from the natural ores are more 
active than those from pure uranium. This discovery 
naturally led to further investigation, on the assump- 
tion that pitchblende contains more than one radio- 
active substance. Polonium, named by Mme. Curie 
in honor of her native country, was the third radio- 
active element to be discovered. In the chemical 
analysis of pitchblende made by Mme. Curie (as- 
sisted by M. Curie) polonium was found associated 
with bismuth. Radium, also discovered in this anal- 
ysis of 1898, was associated with barium. Mme. 
Curie succeeded in obtaining the pure chloride of 


radium and in determining the atomic weight of the 
new element. There is (according to Soddy) about 
one part of radium in five million parts of the best 
pitchblende, but the new element is about one mil- 
lion times more radioactive than uranium. It was 
calculated by M. Curie that the energy of one gram 
of radium would suffice to lift a weight of five hun- 
dred tons to a height of one mile. After discussing 
the bearing of the discovery of radioactivity on the 
threatened exhaustion of the coal supply Soddy 
writes enthusiastically : " But the recognition of the 
boundless and inexhaustible energy of Nature (and 
the intellectual gratification it affords) brightens the 
whole outlook of the twentieth century." The ele- 
ment yields spontaneously radium emanation without 
any apparent diminution of its own mass. In 1899 
Debierne discovered, also in the highly complex 
pitchblende, actinium, which has proved considerably 
less radioactive than radium. During these investi- 
gations M. and Mme. Curie, M. Becquerel, and those 
associated with them were influenced by the hypoth- 
esis that radioactivity is an atomic property of radio- 
active substances. This hypothesis came to definite 
expression in 1899 and again in 1902 through Mme. 

In the latter year the physicist E. Rutherford and 
the chemist F. Soddy, while investigating the radio- 
activity of thorium in the laboratories of McGill 
University, Montreal, were forced to recognize that 
thorium continuously gives rise to new kinds of ra- 
dioactive matter differing from itself in chemical 
properties, in stability, and in radiant energy. They 
concurred in the view held by all the most prominent 


workers in this subject, namely, that radioactivity is 
an atomic phenomenon. It is not molecular decompo- 
sition. They declared that the radioactive substances 
must be undergoing a spontaneous transformation. 
The daring nature of this hypothesis and its likeli- 
hood to revolutionize physical science is brought home 
to one by recalling that three decades previously an 
eminent physicist had said that "though in the 
course of ages catastrophes have occurred and may 
yet occur in the heavens, though ancient systems 
may be dissolved and new systems evolved out of 
their ruins, the molecules [atoms] out of which these 
systems are built the foundation stones of the 
material universe remain unbroken and unworn." 
In 1903 Rutherford and Soddy stated definitely 
their hypothesis, generally known as the " Transfor- 
mation Theory," that the atoms of radioactive sub- 
stances suffer spontaneous disintegration, a process 
unaffected by great changes of temperature (or by 
physical or chemical changes of any kind at the dis- 
posal of the experimenter) and giving rise to new 
radioactive substances differing in chemical (and 
physical) properties from the parent elements. The 
radiations consist of a particles (atoms of helium 
minus two negative electrons), /3 particles, or elec- 
trons (charges of negative electricity), and 7 rays, of 
the nature of Rontgen rays and light but of very much 
shorter wave length and of very great penetrating 
power. It is by the energy inherent in the atom of the 
radioactive substance that the radiations are ejected, 
sometimes, in the case of the 7 rays with velocity 
sufficient to penetrate two feet of lead. It is through 
these radiations that spontaneous transformation 


takes place. After ten years of further investigation 
Rutherford stated that this hypothesis affords a 
satisfactory explanation of all radioactive phenom- 
ena, and gives unity to what without it would seem 
disconnected facts. Besides accounting for old ex- 
perimental results it suggests new lines of work 
and even enables one to predict the outcome of fur- 
ther investigation. It does not really contradict, as 
some thought might be the case, the principle of the 
conservation of energy. The atom, to be sure, can 
no longer be considered the smallest unit of matter, 
as the mass of a ft particle is approximately one 
seventeen-hundredths that of an atom of hydrogen. 
Still the new hypothesis is a modification and not a 
contradiction of the atomic theory. 

The assumption that the series of radioactive sub- 
stances is due, not to such molecular changes as chem- 
istry had made familiar, but to a breakdown of the 
atom seemed to Rutherford in 1913 at least justified 
by the results of the investigators whose procedure 
had been dictated by that hypothesis. He set forth 
in tables these results (since somewhat modified), 
indicating after the name of each radioactive sub- 
stance the nature of the radiation through the emis- 
sion of which the element is transformed into the 
next-succeeding member of its series. 

List of Radioactive Substances 

URANIUM a particles 

Uranium X 
Uranium Y 


RADIUM a 4- slow ft 

Emanation a 

Radium A a 

Radium B 

Radium C 

V. C/2 



Radium E 
Radium F 




MESOTHORIUM 1 no rays 

Meso thorium 2 


Thorium X a 

Emanation a 

Thorium A a 

Thorium B slow 
f 1 


C 2 a 

Thorium D 

ACTINIUM no rays 

Radio-actinium a 4- ft 

Actinium X a 

Emanation a 

Actinium A a 

Actinium B slow 8 

Actinium C a 

Actinium D a-f-y 


Even a glance at this long list of new elements 
reveals certain analogies between one series of trans- 
formations and another. Each series contains an ema- 
nation, or gas, which through the loss of a particles 
is transformed into the next following member of the 
series. Continuing the comparison in either direction, 
up or down the lists, one could readily detect other 

There is some ground for thinking that lead is the 
end product of the Uranium series. To reverse the 
process of the transformation and produce radium from 
the base metal lead would be an achievement greater 
than the vaunted transmutations of the alchemists. 
Although that seems beyond the reach of possibility, 
the idea has stirred the imagination of more than one 
scientist. "The philosopher's stone," writes Soddy, 
" was accredited the power not only of transmuting 
the metals, but of acting as the elixir of life. Now, 
whatever the origin of this apparently meaningless 
jumble of ideas may have been, it is really a perfect 
and but very slightly allegorical expression of the 
actual present views we hold to-day." Again, it is 
conjectured that bismuth is the end-product of the 
thorium series. The presence of the results of atomic 
disintegration (like lead and helium) has proved of 
interest to geology and other sciences as affording a 
clue to the age of the rocks in which they are found 

Before Rutherford, Mme. Curie, and others espe- 
cially interested in radioactive substances, assumed 
that atoms are far different from the massy, hard, im- 
penetrable particles that Newton took for granted, 
Sir J. J. Thomson and his school were studying the 


constitution of the atom from another standpoint but 
with somewhat similar results. This great physicist 
had proved that cathode rays are composed not of 
negatively charged molecules, as had been supposed, 
but of much smaller particles or corpuscles. Wherever, 
as in the vacuum tube, these electrons appear, the 
presence of positively charged particles can also be 
demonstrated. It is manifest that the atom, instead 
of being th3 ultimate unit of matter, is a system of 
positively and negatively charged particles. Ruther- 
ford in the main concurred in this view, though dif- 
fering from Sir J. J. Thomson as to the arrangement 
of corpuscles within the atom. Let it suffice here to 
state that Rutherford assumes that the greater mass 
of the atom consists of negatively charged particles 
rotating about a positive nucleus. The surrounding 
electrons render the atom electrically neutral. 

This corpuscular theory of matter may throw light 
on the laws of chemical combination. The so-called 
chemical affinity between two atoms of such and such 
valencies, which Davy and others since his time had 
regarded as essentially an electrical phenomenon, 
seems now to admit of more definite interpretation. 
Each atom is negatively or positively charged accord- 
ing to the addition or subtraction of electrons. Chemi- 
cal composition takes place between atoms the charges 
of which are of opposite sign, and valency depends on 
the number of unit charges of electricity. Moreover, 
the electrical theory of matter lends support to the hy- 
pothesis that there is a fundamental unitary element 
underlying all the so-called elements. The fact that 
elements fall into groups and that their chemical prop- 
erties vary with their atomic weights long ago sug- 


gested this assumption of a primitive matter, protyl, 
from which all other substances were derived. In the 
light of the corpuscular theory as well as of the trans- 
formation theory it seems possible that the helium 
atom and the negative corpuscle will offer a clue to 
the genesis of the elements. 

What is to be learned from this rapid sketch, of 
the discovery of the radioactive substances, concern- 
ing the nature and value of scientific hypothesis? 
For one thing, the scientific hypothesis is necessary 
to the experimenter. The mind runs ahead of and 
guides the experiment. Again, the hypothesis sug- 
gests new lines of research, enables one in some cases 
to anticipate the outcome of experiment, and may be 
abundantly justified by results. " It is safe to say," 
writes Rutherford, " that the rapidity of growth of 
accurate knowledge of radioactive phenomena has 
been largely due to the influence of the disintegration 
theory." The valid hypothesis serves to explain facts, 
leads to discovery, and does not conflict with known 
facts or with verified generalizations, though, as we 
have seen, it may modify other hypotheses. Those 
who support a hypothesis should bring it to the test 
of rigid verification, avoiding skepticism, shunning 
credulity. Even a false assumption, as we have seen, 
may prove valuable when carefully put to the proof. 

The layman's distrust of the unverified hypothesis 
is in the main wholesome. It is a duty not to believe 
it, not to disbelieve it, but to weigh judicially the evi- 
dence for and against. The fact that assumption plays 
a large part in our mental attitude toward practical 
affairs should make us wary of contesting the legiti- 
macy of scientific hypotheses. 


No one would deny the right of forming a provi- 
sional assumption to the intelligence officer interpret- 
ing a cipher, or to the detective unravelling the mys- 
tery of a crime. The first assumes that the message 
is in a certain language, and, perhaps, that each sym- 
bol employed is the equivalent of a letter ; his assump- 
tion is put to the proof of getting a reasonable and 
consistent meaning from the cipher. The detective 
assumes a motive for the crime, or the employment 
of certain means of escape ; even if his assumption 
does not clear up the mystery, it may have value as 
leading to a new and more adequate assumption. 

Henri Poincare has pointed out that one of the 
most dangerous forms of hypothesis is the uncon- 
scious hypothesis. It is difficult to prove or disprove 
because it does not come to clear statement. The al- 
leged devotee of facts and of things as they are, in 
opposing the assumptions of an up-to-date science, is 
often, unknown to himself, standing on a platform 
of outworn theory, or of mere vulgar assumption. 
For example, when Napoleon was trying to destroy 
the commercial wealth of England at the beginning 
of the nineteenth century, he unconsciously based his 
procedure on an antiquated doctrine of political 
economy. For him the teachings of Adam Smith and 
Turgot were idle sophistries. " I seek," he said to 
his Minister of Finance, " the good that is prac- 
tical, not the ideal best : the world is very old , we 
must profit by its experience ; it teaches that old 
practices are worth more than new theories : you are 
not the only one who knows trade secrets." We are 
not here especially concerned with the question of 
whether Napoleon was or was not pursuing the best 


means of breaking down English credit. He did try 
to prevent the English from exchanging exports for 
European gold, while permitting imports in the hope 
of depleting England of gold. But in pursuing this 
policy he thought he was proceeding on the ground 
of immemorial practice, while he was merely pitting 
the seventeenth-century doctrine of Locke against 
the doctrine of Adam Smith which had superseded it. 

According to one scientific hypothesis, "Species 
originated by means of natural selection, or, through 
the preservation of favored races in the struggle for 
life." This assumption was rightly subjected to close 
scrutiny in 1859 and the years following. The ephem- 
eral nature of the vast majority of hypotheses and 
the danger to progress of accepting an unverified 
assumption justify the demand for demonstrative 
evidence. The testimony having been examined, it 
is our privilege to state and to support the opposing 
hypothesis. It was thus that the hypothesis that the 
planets move in circular orbits, recommended by its 
simplicity and aesthetic quality, was forced to give 
way to the hypothesis of elliptical orbits. Newton's 
hypothesis that light is due to particles emitted by 
all luminous bodies yielded, at least for the time, to 
the theory of light vibrations in an ether pervading 
all space. The path of scientific progress is strewn 
with the ruins of overthrown hypotheses. Many of 
the defeated assumptions have been merely implicit 
errors of the man in the street, and they are over- 
thrown not by facts alone, but by new hypotheses 
verified by facts and leading to fresh discoveries. 

According to John Stuart Mill, " It appears . . . 
to be a condition of a genuinely scientific hypothesis, 


tliat it be not destined always to remain an hypothe- 
sis, but be of such a nature as to be either proved 
or disproved by that comparison with observed facts 
which is termed Verification." This statement is 


of value in confirming the general distrust of mere 
hypothesis, and in distinguishing between the unveri- 
fied and un verifiable presupposition and the legiti- 
mate assumption which through verification may be- 
come established doctrine. 


J. Cox, Beyond the Atom, 1913 (Cambridge Manuals of Science 

and Literature). 

R. K. Duncan, The New Knowledge, 1905. 
H. Poincare, Science and Hypothesis, 

E. Rutherford, Radioactive Substances and their Radiations. 

F. Soddy, The Interpretation of Radium. 

F. Soddy, Matter and Energy (Home University Library). 
Sir William A. Tilden, Progress of Scientific Chemistry in our Own 
Time, 1913. 



PSYCHOLOGY, or the science of mental life as re- 
vealed in .behavior, has been greatly indebted to 
physiologists and to students of medicine in general. 
Any attempt to catalogue the names of those who 
have approached the study of the mind from the 
direction of the natural sciences is liable to prove 
unsatisfactory, and a brief list is sure to entail many 
important omissions. The mention of Locke, Chesel- 
den, Hartley, Cabanis, Young, Weber. Gall, Miil- 
ler, Du Bois-Reymond, Bell, Magendie, Helmholtz, 
Darwin, Lotze, Ferrier, Goltz, Munk, Mosso, Mauds- 
ley, Carpenter, Galton, Hering, Clouston, James, 
Janet, Kraepelin, Flechsig, and Wundt will, however, 
serve to remind us of the richness of the contribu- 
tion of the natural sciences to the so-called mental 
science. Indeed, physiology would be incomplete 
unless it took account of the functions of the sense 
organs, of the sensory and motor nerves, of the brain 
with its association areas, as well as the expression 
of the emotions, and the changes of function accom- 
panying the development of the nervous system, 
from the formation of the embryo till physical disso- 
lution, and from" species of the simplest to those of 
the most complex organization. 

At the beginning of the nineteenth century the 
French physician Cabanis was disposed to identify 
human personality with mere nervous organization 


reacting to physical impressions, and to look upon 
the brain as the organ for the production of mind. 
He soon, however, withdrew from this extreme posi- 
tion and expressed his conviction of the existence of 
an immortal spirit apart from the body. One might 
say that the brain is the instrument through which 
the mind manifests itself rather than the organ by 
which mind is excreted. Even so, it must be agreed 
that the relation between the psychic agent and the 
physical instrument is so close that physiology must 
take heed of mental phenomena and that psychology 
must not ignore the physical concomitants of mental 
processes. Hence arises a new branch of natural 
science, physiological . psychology, or, as Fechner 
(1860), the disciple of Weber, called it, psycho- 

Through this alliance between the study of the 
mind and the study of bodily functions the intelli- 
gence of the lower animals and its survival value, the 
mental growth of the child, mental deterioration in 
age and disease, and the psychological endowments 
of special classes or of individuals, became subjects 
for investigation. Now human psychology is recog- 
nized as contributing to various branches of anthro- 
pology, or the general study of man. 

Wilhelm Wundt, who, as already implied, had ap- 
proached the study of the mind from the side of the 
natural sciences, established in 1875 at the University 
of Leipzig the first psycho-physical institute for the 
experimental study of mental phenomena. His express 
purpose was to analyze the content of consciousness 
into its elements, to examine these elements in their 
qualitative and quantitative differences, and to deter- 


mine with precision the conditions of their existence 
and succession. Thus science after contemplating a 
wide range of outer phenomena plants, animals, 
earth's crust, heavenly bodies, molecules and atoms 
turns its attention with keen scrutiny inward on 
the thinking mind, the subjective process by which 
man becomes cognizant of all objective things. 

The need of expert study of the human mind as 
the instrument of scientific discovery might have been 
inferred from the fact that the physicist Tyndall read 
before the British Association in 1870 a paper on the 
Scientific Use of the Imagination, in which he spoke 
of the imagination as the architect of physical theory, 
cited Newton, Dalton, Davy, and Faraday as afford- 
ing examples of the just use of this creative power 
of the mind, and quoted a distinguished chemist as 
identifying the mental process of scientific discov- 
ery with that of artistic production. Tyndall even 
chased the psychologists in their own field and stated 
that it was only by the exercise of the imagination that 
we could ascribe the possession of mental powers to 
our fellow creatures. " You believe that in society 
you are surrounded by reasonable beings like your- 
self. . . . What is your warrant for this conviction ? 
Simply and solely this : your fellow-creatures behave 
as if they were reasonable." 

On the traces of this brilliant incursion of the 
natural philosopher into the realm of mental science, 
later psychologists must follow but haltingly. Just 
as in the history of physics a long series of studies 
intervened between Bacon's hypothesis that heat is 
a kind of motion (1620) and Tyndall's own work, 
Heat as a Mode of Motion (1863), so must many 


psychological investigations be made before an ade- 
quate psychology of scientific discovery can be formu- 
lated. It may ultimately prove that the passages in 
which Tyndall and other scientists speak of scientific 
imagination would read as well if for this term, in- 
tuition, inspiration, unconscious cerebration, or even 
reason were substituted. 

At first glance it would seem that the study of the 
sensory elements of consciousness, motor, tactile, 
visual, auditory, olfactory, gustatory, thermal, inter- 
nal, pursued for the last half century by the experi- 
mental method, would furnish a clue to the nature of 
the imagination. A visual image, or mental picture, 
is popularly taken as characteristic of the imaginative 
process. In fact, the distinguished psychologist Wil- 
liam James devotes the whole of his interesting 
chapter on the imagination to the discussion of dif- 
ferent types of imagery. The sensory elements of 
consciousness are involved, however, in perception, 
memory, volition, reason, and sentiment, as they are 
in imagination. They have been recognized as fun- 
damental from antiquity. Nothing is in the intellect 
which was not previously in the senses. To be out of 
one's senses is to lack the purposive guidance of 
the intelligence. 

The psychology of individuals and groups shows 
startling: differences in the kind and vividness of 


imagery. Many cases are on record where the mental 
life is almost exclusively in visual, in auditory, or in 
motor terms. One student learns a foreign language 
by writing out every word and sentence ; another is 
wholly dependent on hearing them spoken ; a third 
can recall the printed page with an almost photo- 


graphic vividness. The history of literature and art 
furnishes us with illustrations of remarkable powers 
of visualization. Blake and Fromentin were able to 
reproduce in pictures scenes long retained in memory. 
The latter recognized that his painting was not an 
exact reproduction of what he had seen, but that it 
was none the less artistic because of the selective influ- 
ence that his mind had exerted on the memory image. 
Wordsworth at times postponed the description of a 
scene that appealed to his poetic fancy with the ex- 
press purpose of blurring the outlines, but enhancing 
the personal factor. Goethe had the power to call up 
at will the form of a flower, to make it change from 
one color to another and to unfold before his mind's 
eye. Professor Dilthey has collected many other 
records of the hallucinatory clearness of the visual 
imagery of literary artists. 

On the other hand, Galton, after his classical 
study of mental imagery (1883), stated that scientific 
men, as a class, have feeble powers of visual repre- 
sentation. He had appealed for evidence of visual 
recall to distinguished scientists because he thought 
them more capable than others of accurately stating 
the results of their introspection. He had recourse 
not only to English but to foreign scientists, includ- 
ing members of the French Institute. " To my aston- 
ishment," he writes, " I found that the great majority 
of men of science to whom I first applied protested 
that mental imagery was unknown to them, and they 
looked on me as fanciful and fantastic in supposing 
that the words ' mental imagery ' really expressed 
what I believed everybody supposed them to mean. 
They had no more notion of its true nature than a 


color-blind man, who has not discerned his defect, 
has of the nature of color." One scientist confessed 
that it was only by a figure of speech that he could 
describe his recollection of a scene as a mental image 
to be perceived with the mind's eye. 

When Galton questioned persons whom he met in 
general society he found " an entirely different dispo- 
sition to prevail. Many men and a yet larger number 
of women, and many boys and girls, declared that 
they habitually saw mental imagery, and that it was 
perfectly distinct to them and full of color." The 
evidence of this difference between the psychology 
of the average distinguished scientist and the average 
member of general society was greatly strengthened 
upon cross-examination. Galton attributed the differ- 
ence to the scientist's " habits of highly generalized 
and abstract thought, especially when the steps of 
reasoning are carried on by words [employed] as 

It is only by the use of words as symbols that sci- 
entific thought is possible. It is through cooperation 
in work that mankind has imposed its will upon the 
creation, and cooperation could not have been carried 
far without the development of language as a means of 
communication. Were it not for the help of words 
we should be dependent, like the lower animals, on 
the fleeting images of things. We should be bound 
to the world of sense and not have range in the world 
of ideas. Words are a free medium for thought, for 
the very reason that they are capable of shifting 
their meaning and taking on greater extension or in- 
tension. For example, we may say that the apple falls 
because it is heavy, or we may substitute synonymous 


phraseology that helps us to view the falling apple in 
its universal aspects. The mind acquires through 
language a field of activity independent of the ob- 
jective world. We have seen in an earlier chapter 
that geometry developed as a science in becoming 
gradually weaned from the art of surveying. Tri- 
angles and rectangles cease to suggest meadows, or 
vineyards, or any definite imagery of that sort, and 
are discussed in their abstract relationship. Science 
demands the conceptual rather than the merely sen- 
sory. The invisible real world of atoms and cor- 
puscles has its beginning in the reason, the word. To 
formulate new truths in the world of ideas is the pre- 
rogative of minds gifted with exceptional reason. 

To be sure, language itself may be regarded as im- 
agery. Some persons visualize every word spoken as 
though it were seen on the printed page ; others can- 
not recall a literary passage without motor imagery 
of the speech organs or even incipient speech ; while 
others again experience motor imagery of the writing 
hand. With many, in all forms of word -conscious- 
ness, the auditory image is predominant. In the 
sense of being accompanied by imagery all think- 
ing is imaginative. But it is the use of words 
that permits us to escape most completely from the 
more primitive forms of intelligence. So directly 
does the printed word convey its meaning to the 
trained mind that to regard it as so much black on 
white rather than as a symbol is a rare and rather 
upsetting mental experience. Words differ among 
themselves in their power to suggest images of the 
thing symbolized. The word " existence " is less image- 
producing than "flower," and "flower" than "red 


rose." It is characteristic of the language of science 
to substitute the abstract or general expression for 
the concrete and picturesque. 

When, therefore, we are told that the imagination 
has been at the bottom of all great scientific discov- 
eries, that the discovery of law is the peculiar function 
of the creative imagination, and that all great scien- 
tists have, in a certain sense, been great artists, we 
are confronted with a paradox. In what department 
of thought is imagination more strictly subordinated 
than in science ? Genetic psychology attempts to trace 
the development of mind as a means of adjustment. 
It examines the instincts that serve so wonderfully 
the survival of various species of insects. It studies 
the more easily modified instinct of birds, and notes 
their ability to make intelligent choice on the basis 
of experience. Does the bird's ability to recognize 
imply the possession of memory, or imagery? In- 
creased intelligence assures perpetuation of other 
species in novel and unforeseen conditions. The more 
tenacious the memory, the richer the supply of images, 
the greater the powers of adaptation and survival. 
We know something concerning the motor memory 
of rodents and horses, and its biological value. The 
child inherits less definitely organized instincts, but 
greater plasticity, than the lower animals. Its mental 
life is a chaos of images. It is the work of education 
to discipline as well as to nourish the senses, to teach 
form as well as color, to impart the clarifying sense 
of number, weight, and measurement, to help distin- 
guish between the dream and the reality, to teach 
language, the treasure-house of our traditional wis- 
dom, and logic, so closely related to the right use of 


language. The facts of abnormal, as well as those of 
animal and child psychology, prove that the subor- 
dination of the imagination and fancy to reason and 
understanding is an essential factor in intellectual 

No one, of course, will claim that the mental ac- 
tivity of the scientific discoverer is wholly unlike 
that of any other class of man ; but it leads only to 
confusion to seek to identify processes so unlike as 
scientific generalization and artistic production. The 
artist's purpose is the conveyance of a mood. The 
author of Macbeth employs every device to impart to 
the auditor the sense of blood-guiltiness ; every lurid 
scene, every somber phrase, serves to enhance the 
sentiment. A certain picture by Diirer, a certain 
poem of Browning's, convey in every detail the feel- 
ing of dauntless resolution. Again, a landscape 
painter, recognizing that his satisfaction in a certain 
scene depends upon a stretch of blue water with a 
yellow strand and old-gold foliage, proceeds to re- 
arrange nature for the benefit of the mood he desires 
to enliven and perpetuate. It is surely a far cry from 
the attitude of these artists manipulating impressions 
in order to impart to others an individual mood, to 
that of the scientific discoverer formulating a law 
valid for all intellects. 

In the psychology of the present day there is much 
that is reminiscent of the biological psychology of 
Aristotle. From the primitive or nutrient soul which 
has to do with the vital functions of growth and re- 
production, is developed the sentient soul, concerned 
with movement and sensibility. Finally emerges the 
intellectual and reasoning soul. These three parts 


are not mutually exclusive, but the lower foreshadow 
the higrher and are subsumed in it. Aristotle, how- 

O ' 

ever, interpreted the lower by the higher and not 
vice versa. It is no compliment to the scientific dis- 
coverer to say that his loftiest intellectual achievement 
is closely akin to fiction, or is the result of a mere 
brooding on facts, or is accompanied by emotional 
excitement, or is the work of blind instinct. 

It will be found that scientific discovery, while 
predominantly an intellectual process, varies with the 
nature of the phenomena of the different sciences 
and the individual mental differences of the discover- 
ers. As stated at the outset the psychology of scientific 
discovery must be the subject of prolonged investi- 
gation, but some data are already available. One great 
mathematician, Poiucare, attributes his discoveries 
to intuition. The essential idea comes with a sense 
of illumination. It is characterized by suddenness, 
conciseness, and immediate certainty. It may come 
unheralded, as he is crossing the street, walking on 
the cliffs, or stepping into a carriage. There may 
have intervened a considerable period of time free 
from conscious effort on the special question involved 
in the discovery. Poincare is inclined to account for 
these sudden solutions of theoretical difficulties on 
the assumption of long periods of previous uncon- 
scious work. 

There are many such records from men of genius. 
At the moment the inventor obtains the solution of 
his problem his mind may seem to be least engaged 
with it. The long-sought-for idea comes like an in- 
spiration, something freely imparted rather than 
voluntarily acquired. No mental process is more 


worthy to command respect ; but it may not lie be- 
yond the possibility of explanation. Like ethical 
insight, or spiritual illumination, the scientific idea 
comes to those who have striven for it. The door may 
open after we have ceased to knock, or the response 
come when we have forgotten that we sent in a call ; 
but the discovery comes only after conscious work. 
The whole history of science shows that it is to the 
worker that the inspiration comes, and that new 
ideas develop from old ideas. 

It may detract still further from the mysterious- 
ness of the discovery-process to add that the illu- 
minating idea may come in the midst of conscious 
work, and that then also it may appear as a sudden 
gift rather than the legitimate outcome of mental 
effort. T^he spontaneity of wit may afford another clue 
to the mystery of scientific discovery. The utterer of 
a witticism is frequently as much surprised by it as 
the auditors, probably because the idea comes as 
verbal imagery, and the full realization of their sig- 
nificance is grasped only with the actual utterance of 
the words. The fact that to the scientific discoverer 
the solution of his problem arrives at the moment 
when it is least sought is analogous to the common 
experience that the effort to recall a name may in- 
hibit the natural association. 

The tendency to emphasize unduly the role played 
by the scientific imagination springs probably from the 
misconception that the imagination is a psychological 
superfluity, one of the luxuries of the mental life, 
which should not be withheld from those who deserve 
the best. The view lingers with regard to the aesthetic 
imagination. James could not understand the biologi- 


cal function of the aesthetic faculty. On the alleged 
uselessness of this phase of the human mind A. J. Bal- 
four has recently based an argument for the immortal- 
ity of the soul. This view is strikingly at variance 
with that which inclines to identify it with that mental 
process which creates scientific theories and thus paves 
the way for the adjustment of posterity to earthly 


Baldwin, J. M., History of Psychology, 1913. 2 vols. 

Dessoir, Max, Outlines of the History of Psychology, 1912. 

Klemm, Otto, A History of Psychology, 1914. 

Merz, J. T., History of European Thought in the Nineteenth Cen- 
tury, vol. n, chap, xn, On the Psycho-physical View of 

Rand, Benjamin, The Classical Psychologists, 1912. 

Ribot, T. A., English Psychology, 1889. 

Ribot, T. A., German Psychology of To-day, 1886. 



EDUCATION is the oversight and guidance of the 
development of the immature with certain ethical 
and social ends in view. Pedagogy, therefore, is based 
partly on psychology which, as we have seen in 
the preceding chapter, is closely related to the bio- 
logical sciences and partly on ethics, or the study 
of morals, closely related to the social sciences. These 
two aspects of education, the psychological and the 
sociological, were treated respectively in Rousseau's 
Emile and Plato's Republic. The former ill-under- 
stood work, definitely referring its readers to the 
latter for the social aspect of education, applies itself 
as exclusively as possible to the study of the physical 
and mental development of the individual child. 
Rousseau consciously set aside the problem of na- 
tionality or citizenship; he was cosmopolitan, and 
explicitly renounced the idea of planning the educa- 
tion of a Frenchman or a Swiss. Neither did he desire 
to set forth the education of a wild man, free and 
unrestrained. He wished rather to depict the devel- 
opment of a natural man in a state of society ; but 
he emphasized the native hereditary endowment, 
while expressing his admiration for Plato's Republic 
as the great classic of social pedagogy. The titles of the 
two works, one from the name of an individual child, 
the other from a form of government, should serve 
to remind us of the purpose and limitations of each. 


Plato's thought was centered on the educational 
and moral needs of the city-state of Athens. He was 
apprehensive that the city was becoming corrupted 
through the wantonness and lack of principle of the 
Athenian youth. He strove to rebuild on reasoned 
foundations the sense of social obligation and re- 
sponsibility which had in the earlier days of Athens 
rested upon faith in the existence of the gods. As a 
conservative he hoped to restore the ancient Athenian 
feeling for duty and moral worth, and he even en- 
vied some of the educational practices of the rival 
city-state Sparta, by which the citizen was subordi- 
nated to the state. The novel feature of Plato's ped- 
agogy was the plan to educate the directing classes, 
men disciplined in his own philosophical and ethical 
conceptions. He was, in fact, an intellectual aristo- 
crat, and spoke of democracy in very ironical terms, 
as the following sentences will show : 

" And thus democracy comes into being after the 
poor have conquered their opponents. . . . And now 
what is their manner of life, and what sort of a gov- 
ernment have they? For as the government is, such 
will be the man. ... In the first place, are they 
not free ? and the city is full of freedom and frank- 
ness a man may do as he likes. . . . And where 
freedom is, the individual is clearly able to order his 
own life as he pleases ? . . . Then in this kind of 
State there will be the greatest variety of human na- 
tures ? . . . This then will be the fairest of States, 
and will appear the fairest, being spangled with the 
manners and characters of mankind, like an em- 
broidered robe which is spangled with every sort 
of flower. And just as women and children think 


variety charming, so there are many men who will 
deem this to be the fairest of States. . . . And is not 
the equanimity of the condemned often charming? 
Under such a government there are men who, when 
they have been sentenced to death or exile, stay 
where they are and walk about the world ; the gen- 
tleman [convict] parades like a hero, as though no- 
body saw or cared. . . . See too . . . the forgiv- 
ing spirit of democracy and the ' don't care ' about 
trifles, and the disregard of all the fine principles 
which we solemnly affirmed . . . how grandly does 
she trample our words under her feet, never giving 
a thought to the pursuits which make a statesman, 
and promoting to honor anyone who professes to be 
the people's friend. . . . These and other kindred 
characteristics are proper to democracy, which is a 
charming form of government, full of variety and 
disorder, and dispensing equality to equals and un- 
equals alike. . . . Consider now . . . what manner 
of man the individual is ... he lives through the 
day indulging the appetite of the hour ; and some- 
times he is lapped in drink and strains of the flute ; 
then he is for total abstinence, and tries to get thin ; 
then, again, he is at gymnastics ; sometimes idling 
and neglecting everything, then once more living 
the life of a philosopher ; often he is in politics, and 
starts to his feet and says and does whatever comes 
into his head ; and, if he is emulous of anyone who 
is a warrior, off he is in that direction, or of men of 
business, once more in that. His life has neither 
order nor law; so he goes on continually, and he 
terms this joy and freedom and happiness. Yes, his 
life is all liberty and equality. Yes, . . . and multi- 


form, and full of the most various characters ; . . . 
he answers to the State, which we described as fair 
and spangled. . . . Let him then be set over against 
democracy; he may truly be called the democratic 


In spite of the satirical tone of this passage much 
of it may be accepted as the unwilling tribute of 
a hostile critic. Democracy is the triumph of the 
masses over the oligarchs. It is merciful in the ad- 
ministration of justice. It shows a magnanimous 
spirit and does not magnify the importance of trifles. 
It prefers the rule of its friends to the rule of a 
despot. Under its government people feel themselves 
blessed by happiness, liberty, and equality. The 
culture of the democratic man is above all charac- 
terized by adaptability. 

In the nineteenth century Matthew Arnold, the 
apostle of culture, discussing the civilization of a 
democratic nation of many millions, unconsciously 
confirmed the views of Plato in some respects, while 
showing interesting points of difference. He ex- 
pressed his admiration of the institutions, solid social 
conditions, freedom and equality, power, energy, and 
wealth of the people of the United States. In the 
daintiness of American house-architecture, and in 
the natural manners of the free and happy Amer- 
ican women he saw a real note of civilization. He 
felt that his own country had a good deal to learn 
from America, though he did not close his eyes to 
the real dangers to which all democratic nations are 
exposed. Arnold failed in his analysis of American 
civilization to confirm Plato's judgment concerning 
the variety of natures to be found in the democratic 


State, as well as the Greek philosopher's censure 
that democracy shows disregard of ethical principles. 
In fact, Arnold considered the people of the United 
States singularly homogeneous, singularly free from 
the distinctions of class ; " we [the English] are so 
little homogeneous, we are living with a system of 
classes so intense, that the whole action of our minds 
is hampered and falsened by it ; we are in conse- 
quence wanting in lucidity, we do not see clear or 
think straight, and the Americans have here much 
the advantage of us." As for the second point of 
difference between Arnold and Plato, the English 
critic recognized that the American people belonged 
to the great class in society in which the sense of 
conduct and regard for ethical principles are par- 
ticularly developed. 

Nearly all the old charges against American democ- 
racy can be summarized in one general censure, 
the lack of calm and reasoned self-criticism, and 
this general defect is rapidly being made good. It is 
partly owing to charity and good-will, and it includes 
the toleration of the mediocre or inferior, as, for ex- 
ample, in the theater ; the failure to recognize dis- 
tinction, and to pay deference to things deserving it ; 
the glorification of the average man, and the hustler, 
and the lack of special educational opportunities for 
the exceptionally gifted child. That criticism as an 
art is still somewhat behindhand in America seems 
to be confirmed by comparing French and American 
literary criticism. In France it is a profession prac- 
ticed by a corps of experts ; in America only a very 
few of the best periodicals can be relied on to give 
reviews based on critical principles, of works in verse 


or prose. (One American reviewer confesses that in 
a single day lie has written notices of twenty new 
works of fiction, his work bringing him, as remu- 
neration, seventy-five cents a volume.) 

There is no evidence, however, that Americans as 
individuals are wanting in the self-critical spirit. 
And for Arnold this is vital, seeing that the watch- 
word of the culture he proclaims is Know Thyself. 
It is not a question of gaining a social advantage by 
a smattering of foreign languages. It is more than 
intellectual curiosity. " Culture is more properly de- 
scribed as having its origin in the love of perfection. 
It moves by the force, not merely or primarily of the 
scientific passion for pure knowledge, but also of 
the passion for doing good." Human perfection, the 
essence of culture, is an internal condition, but the 
will to do good must be guided by the knowledge of 
what is good to do ; " acting and instituting are of 
little use unless we know how and what we ought to 
act and institute." Moreover, " because men are all 
members of one great whole, and the sympathy which 
is human nature will riot allow one member to be 
indifferent to the rest, the expansion of our human- 
ity, to suit the idea of perfection which culture forms, 
must be a general expansion." 

For Arnold's contemporary Nietzsche, the German 
exponent of Aristocracy, the expansion of education 
entailed its diminution. For him ancient Greece was 
the only home of culture, and such culture was not 
for all comers. The rights of genius are not to be 
democratized ; not the education of the masses, but 
rather the education of a few picked men must be 
the aim. The one purpose which education should 


most zealously strive to achieve is the suppression of 
all ridiculous claims to independent judgment, and 
the inculcation upon young men of obedience to the 
scepter of genius. The scientific man and the cul- 
tured man belong to two different spheres which, 
though coming together at times in the same indi- 
vidual, are never fully reconciled. 

In order to appreciate the full perverseness, from 
the democratic standpoint, of Nietzsche's view of 
culture, it is necessary to glance at his political ideals 
as explained by one of his sponsors. Nietzsche re- 
pudiates the usual conception of morality, which he 
calls slave-morality, in favor of a morality of mas- 
ters. The former according to him encourages the 
deterioration of humanity ; the latter promotes ad- 
vancement. He favors a true aristocracv as the best 


means of producing a race of supermen. " Instead 
of advocating ' equal and inalienable rights to life, 
liberty, and the pursuit of happiness,' for which 
there is at present such an outcry (a regime which 
necessarily elevates fools and knaves, and lowers the 
honest and intelligent), Nietzsche advocates simple 
justice to individuals and families according to 
their merits, according to their worth to society ; 
not equal rights, therefore, but unequal rights, and 
inequality in advantages generally, approximately 
proportionate to deserts ; consequently, therefore, a 
genuinely superior ruling class at one end of the 
social scale, and an actually inferior ruled class, with 
slaves at its basis, at the opposite social extreme." 

Since it is the view of this aristocratic philosopher 
that science is the ally of democracy a view that 
every chapter of the history of science serves to dem- 


onstrate it is of interest to review his opinion of 
the character of the scientist. For Nietzsche the sci- 
entist is not a heroic superman, but a commonplace 
type of man, with commonplace virtues. He lacks 
domination, authority, self-sufficiency ; he is rather 
in need of recognition from others and is character- 
ized by the self-distrust innate in all dependent men 
and gregarious animals. He is industrious, patiently 
adaptable to rank and file, equable and moderate in 
capacity and requirement. He has a natural feeling 
for people like himself, and for that which they re- 
quire : A fair competence and the green meadow 
without which there is no rest from labor. The 
scientist shows no rapture for exalted views ; in 
fact, with an instinct for mediocrity, he is envious 
and strives for the destruction of the exceptional 

A training: in natural science tends to make one 


objective. But the objective man, in Nietzsche's 
opinion, distrusts his own personality and regards it 
as something to be set aside as accidental, and a 
detriment to calm judgment. The temperamental 
philosopher thinks the scientist serene, but that his 
serenity springs not from lack of trouble, but from 
incapacity to grasp and deal with his own private 
grief. His is merely disinterested knowledge, accord- 
ing to Nietzsche. The scientist is emotionally im- 
poverished. His love is constrained, and his hatred 
artificial ; he is less interesting to women than the 
warrior. " His mirroring and externally self-polished 
soul no longer knows how to affirm, no longer how 
to deny ; he does not command ; neither does he 
destroy." As we see in the case of Leibnitz, the 


scientist contemns scarcely anything (Je ne meprise 
presque rien). The scientist is an instrument, but 
not a goal ; he is something of a slave, nothing in 
himself presque rien! There is in the scientist 
nothing bold, powerful, self-centered, that wants to 
be master. He is for the most part a man without 
content and definite outline, a selfless man. 

This educational product, which the builders of 
modern aristocracy reject, and describe after their 
fashion, we accept as the ally of the masses of the 
people, and we term it democratic culture. 

The objective man, at the same time, may find 
even in the vehement pages of Nietzsche warnings 
and criticisms which the friends of democracy should 
not disregard. Extreme, almost insane, as his doc- 
trine undoubtedly is, it may have value as a correc- 
tive influence, an antidote for other extreme views. 
It serves to remind us that democracy may be mis- 
led by feelings in themselves noble, and may, by 
grasping what seems good, miss what is best. For 
example, there are in the United States about three 
hundred thousand persons defective or subnormal 
mentally ; there is a smaller number of persons excep- 
tionally gifted mentally. It is a poor form of social 
service that would exhaust the resources of science 
and philanthropy to care for the former without 
making any special provision for the latter. Genius 
is too great an asset to be wasted or misapplied. All 
culture would have suffered if Newton had been 
held, in his early life, to exacting administrative 
work ; or if Darwin had devoted his years to allevi- 
ating the conditions of the miners of Peru whose 
misery touched him so profoundly ; or if Pasteur had 


been taken from the laboratory and pure science to 
make a country doctor. Nor can democracy rest sat- 
isfied with any substitute for culture which would 
disregard what is great in literature, in art, and in 
philosophy, or which would ignore history, and the 
languages and civilizations of the past, as if culture 
had its beginning yesterday. 

In this chapter we have considered democracy and 
democratic culture from the standpoint of three 
writers on education, a Greek aristocrat, a German 
advocate of the domination of the classes over the 
masses, and an Oxford professor, all by training and 
temperament more or less hostile critics. A more 
direct procedure might have been employed to es- 
tablish the claim of science to afford a basis of intel- 
lectual and social homogeneity. A brilliant literary 
man of the present day considers that places in the 
first ranks of literature are reserved for the doctri- 
nally heterodox. None of the great writers of Europe, 
he asserts, have been the adherents of the traditional 
faith. (He makes an exception in favor of Racine : 
but this is a needless concession, for Racine owed 
his early education to the Port Royalists, became 
alienated from them and wrote under the inspiration 
of the idea of the moral sufficiency of worldly honor ; 
then, after an experience that shook his faith in his 
own code, he returned to the early religious influ- 
ences in his life and composed his Esther and Atha- 
lie.) But, unlike literature, the study of science is 
not exclusive. In the front ranks of science stand the 
devout Roman Catholic Pasteur, the Anglican Dar- 
win, the Unitarian Priestley, the Calvinist Faraday, 
the Quakers Dalton, Young, and Lister, Huxley the 


Agnostic, and Aristotle the pagan biologist. Science 
has no Test Acts. 

That the cultivation of the sciences tends to pro- 
mote a type of culture that is democratic rather than 
aristocratic, sympathetic rather than austere, inclu- 
sive rather than exclusive, is further witnessed by 
the fact that the tradesman and artisan, as well as 
the dissenter, play a large part in their development. 
We have seen that Pasteur was the son of a tan- 
ner, Priestley of a cloth-maker, Dalton of a weaver, 
Lambert of a tailor, Kant of a saddler, Watt of a 
shipbuilder, Smith of a farmer. John Ray was, like 
Faraday, the son of a blacksmith. Joule was a 
brewer. Davy, Scheele, Dumas, Balard, Liebig, 
Wohler, and a number of other distinguished chem- 
ists, were apothecaries' apprentices. Franklin was 
a printer. At the same time other ranks of society 
are represented in the history of science by Boyle, 
Cavendish, Lavoisier. The physicians and the sons 
of physicians have borne a particularly honorable 
part in the advancement of physical as well as men- 
tal science. The instinctive craving for power, the 
will to dominate, of which Nietzsche was the lyricist, 
was in these men subdued to patience, industry, and 
philanthropy. The beneficent effect of their activities 
on the health and general welfare of the masses of 
the people bears witness to the sanity and worth of 
the culture that prompted these activities. 

As was stated at the outset of this chapter, educa- 
tion is the oversight and guidance of the development 
of the immature with certain ethical and social ends 
in view. The material of instruction, the method of 
instruction, and the type of educational institution, 


will vary with the hereditary endowment, age, and 
probable social destiny of the child. In a democratic 
country likely to become more, rather than less, demo- 
cratic, those subjects will naturally be taught which 
have vital connection with the people's welfare and 
progress in civilization. At the same time the method 
of instruction will be less dogmatic and more in- 
clined (under a free than under an absolute govern- 
ment) to evoke the child's powers of individual judg- 
ment ; arbitrary discipline must yield gradually to 
self-discipline. The changes here indicated as de- 
sirable are already well under way in America. As 
regards types of educational institution, it is signifi- 
cant that America about the middle of the eighteenth 
century introduced the Miltonic, nonconformist 
Academy, with its science curriculum, in place of 
the traditional Latin grammar school. Later the 
American high school, institutions of which type now 
have over a million pupils, and teach science by the 
heuristic laboratory method, became the popular form 
of secondary school. It is, likewise, not without 
social significance that the Kindergarten was sup- 
pressed in Prussia after the revolt of the people in 
the middle of the nineteenth century, and that it 
found a more congenial home in a democratic coun- 
try. Its educational ideal of developing self-activity 
without losing sight of the need of social adapta- 
tion finds its corollary in systematic teaching of the 
sciences in relation both to the daily work and to 
their historical and cultural antecedents. 



Matthew Arnold, Essays in Criticism, and Culture and Anarchy. 

Matthew Arnold, Civilization in the United States. 

Friedrich Nietzsche, On the Future of our Educational Institu- 
tions, vol. vi, of the Complete Works; translation edited by 
Dr. Oscar Levy. 

Friedrich Nietzsche, Beyond Good and Evil, vol. v, chap, vi, of 
the Complete Works. 

Plato, Republic, Book vm; vol. in, of Benjamin Jowett's trans- 
lation of the Dialogues of Plato, 1875. 


Acade'mie des Sciences, 111,112. 

Academy, at Athens, 19; Mil- 
ton's plan, 102; Defoe's, 116; 
Franklin's, 125; type of sec- 
ondary school, 282. 

Adams, John Couch, 188 et seq. 

Aerodynamics, 233. 

Agricola, George, 129. 

Agriculture, 12, 38, 107, 126, 137. 

Air, 157. 

Air craft, 71, 126, 231 et seq, 

Air-pump, 96. 

Akademie der Wissenschaften, 

Albertus Magnus, 53. 

Alchemy, 50, 252. 

Alcuin, 52. 

Alexandria, 19, 44 et seq. 

Algebra, 49. 

Alkaline earths, 179. 

American Philosophical Society, 

Anatomy, 6, 8, 38, 50, 78. 

Anemometer, 107, 235. 

Anthrax, 224 et seq. 

Antipodes, 37, 48. 

Antiseptic surgery, 220, 231. 

Application, 30 et seq. 

Aqua regia, 51, 132. 

Aqueducts, 33. 

Aqueous vapor, 157 et seq. 

Arago, 184. 

Archimedes, 27. 

Architecture, 30 et seq. 

Archytas, 18. 

Aristotle, 20 et seq., 49, 51, 53, 

Arithmetic, 6, 11, 48. 

Arnold, Matthew, 273. 

Astrology, 10. 

Astronomy, (Egyptian and Ba- 
bylonian) Zetseq.; (Greek) 16; 
(Roman) 34; (Alexandrian) 45; 
(Hindu) 48; (Arabian) 49, 50; 
(Copernican) 55 ; (Tycho 
Brahe and Kepler) 87 et seq. ; 
(Newton) 110 et seq.; (nebu- 
lar hypothesis) 142 et seq.; 
(discovery of Neptune) 184 
et seq. 

Atmosphere, 157. 

Atomic Theory, 158 et seq., 250. 

Atoms, 17, 148, 158, 253. 

Augustus Caesar, 36. 

Averroes, 51 et seq. 

Avicenna, 51. 

Avogadro, 165. 

Babylonia, 1 et seq. 

Bacon, Francis, 57 et seq., 80 et 

seq., 105; Baconian principles, 


Bacon, Roger, 54. 
Bacteria, 93. 
Bacteriology, 213 et seq. 
Bagdad, 49. 
Barbarians, 46. 
Barometer, 94 et seq. 
Basalt, 131, 132, 136, 137, 201. 
Becquerel, 233, 246 et seq. 
Beddoes, 173. 
Beer, 223, 226. 
Berzelius, 162. 
Bessel, 187. 
Biology, 6, 7, 23 et seq., 37, 53, 

78, 109, 197 et seq., 213. 



Biot, 215 et seq. 

Black, 129, 133. 

Bodes Law, 189. 

Botany, 6, 26, 37, 39, 53, 231 

et seq. 

Bouvard, Alexis, 185. 
Bouvard, Eugene, 187. 
Boyle, 96, 107. 
Buffon, 130, 135. 
Building material, 32. 

Cabanis, 258. 

Cairo, 49. 

Calendar, 9, 36. 

Carbonic acid, 138, 155, 157, 


Carlisle, 177. 
Cato, 35, 38. 
Challis, 189. 
Charlemagne, 52. 
Charles II, 105. 
Chemical affinity, 159, 253. 
Chemistry, 6, 8, 50, 51, 155 et 

seq., 170 et seq., 245 et seq. 
Chicken cholera, 225. 
Chlorine, 180. 
Clocks, 89, 94. 
Collinson, 123. 
Columbus, 26, 54. 
Columella, 38. 
Comenius, 100. 
Comets, 10, 40, 149. 
Conservation of energy, 168. 
Constantine, 37. 
Copernicus, 55. 
Coral reefs, 203. 
Cordova, 50. 

Counting, 6, 11, 34, 49, 86. 
Cowley, 104 et seq. 
Cronstedt, 130. 
Curie, P. and S., 247 et seq. 

D'Alembert, 58. 
Dalton, 155, 157 et seq. 

Darwin, Charles, 1 98 et seq. 

Darwin, Erasmus, 199. 

Davy, 122, 163, 170 et seq. 

Deduction, 82. 

Defoe, 116. 

Democratic culture, 44, 270 et 


Democritus, 17, 48, 148. 
Descartes, 57, 72, 82 et seq. 
Desmarest, 132. 
Dialogues of Plato, 19. 
Diderot, 58. 
Dioscorides, 39. 
Dyes, 24, 33, 71, 181. 

Earthquakes, 40, 137. 
Ebers papyrus, 7. 
Eclipses, 10, 16, 49. 
Education, 19, 35, 36, 40, 44, 52, 

53, 100 et seq., 116, 122, 123, 

171-72, 198, 213, 214, 216, 

270 et seq. 
Egypt, 1 et seq. 
Electricity, 75, 123 et seq., 177. 


Electrolysis, 178. 
Elements, 17, 20, 22, 155. 
Ellipse, 20. 
Embalmers, 7. 
Empedocles, 17, 40. 
Encyclopaedia, 58. 
Ethics, 21, 40, 41. 
Euclid, 18, 19. 
Evelyn, 109. 
Experiment, 72 et seq. 
Extinction, 206. 

Faraday, 181. 
Fermentation, 216 et seq. 
Fitzroy, 198. 
Flacherie, 221. 
Flamsteed, 110, 111, 184. 
Fossils, 140. 
Franklin, 15. 114. 



Galen, 38, 79. 
Galileo, 75 et seq., 95. 
Galipagos Archipelago, 208 et 


Galle, 193. 
Gallon, 258. 
Galvani, 177. 
Gascoigne, 93. 
Gassendi, 99. 
Gay-Lussac, 164, 181. 
Geber, 177. 
Geology, 129 et seq. 
Geometry, 4, 15, 18, 19, 84, 264. 
Gerbert, 53. 
Gilbert, 72, 74, 76. 
Glen Tilt, 136. 
Gnomon, 13, 33. 
Granite, 131. 
Graunt, 105, 109. 
Gravity, 110 et seq. 
Greece, 15 et seq. 
Gresham College, 101, 106. 
Grew, 109. 
Guericke, 96. 

Hall, Sir James, 129, 137 et seq. 

Halley, 110, 112, 186. 

Hammurabi, 12. 

Hartley, 172, 258. 

Hartlib, 99. 

Harun Al-Rashid, 48. 

Heat, 82, 155, 156, 166, 168, 173. 

Heliacal rising, 4. 

Helmholtz, 168, 258. 

Henry, 238. 

Heraclitus, 17. 

Herschel, Sir John, 192. 

Herschel, Sir William, 152 et 
seq., 184. 

Hindu arithmetic and astron- 
omy, 48, 49. 

Hipparchus, 27, 45. 

Hippocrates, 27. 

Hobbes, 99. 

Homology, 26. 

Hooke, 107, 109. 

Hope, 138. 

Horrocks, 109. 

Horse, 204. 

Horticulture, 40. 

Hugo of St. Victor, 60. 

Humboldt, 131, 201. 

Hussey, 186. 

Hutton, 132 et seq. 

Huygens, 94, 111. 

Hydrophobia, 207, 227 et seq. 

Hypatia, 46, 48. 

Hypothesis, 147, 150, 245 et seq. 

I-em-hetep, 6. 

Ilu-bani, 12. 

Induction, 81, 177. 

Industries, 8, 27, 68 et seq., 173, 

182, 220, 223, 226. 
Inoculation, 126. 
Inventions, 107, 233 et seq. 
Invisible College, 103. 
Iodine, 181. 
Iron, 8, 13, 182. 
Isidore of Seville, 60. 

James, William, 258, 261, 268. 
Joule, 155, 167 et seq. 
Julius Caesar, 36. 

Kant, 142, 145 et seq. 
Kepler, 90 et seq., 110. 
Kindergarten, 281. 
Kircher, 93. 

Lactantius, 48. 
Lambert, 142, 149 et seq. 
Langley, 231 et seq. 
Laplace, 112, 150 et seq. 
Laurium, 27. 
Lava, 138. 
Lavoisier, 156, 172. 
Leeuwenhoek, 93. 



Leibnitz, 106, 112, 277. 
Lenses, 40, 50. 
Leonardo da Vinci, 72. 
Leverrier, 190 et seq. 
Libraries, 46, 48, 121. 
Lincoln, 43 et seq. 
Linnaeus, 130. 
Lippershey, 92. 
Lister, 213, 220, 223. 
Locke, 116, 172, 258. 
Logarithms, 91. 
Logic, 21, 53. 
Lucretius, 40. 
Lyell, 197, 201. 

Magnetism, 75, 127. 

Magnifiers, 40. 

Malpighi, 93, 106, 109. 

Malthus, 121, 211. 

Manchester, 157. 

Marble, 139. 

Mars, 10, 91. 

Marsh gas, 126, 163, 182. 

Materia medica, 39, 51. 

Mathematics, 4, 5, 6, 10, 11, 15, 

17, 18, 19, 34, 48, 49, 55, 87 

et seq., 110 et seq., 184 et seq., 


Maupertuis, 145. 
Mayow, 156. 

Measuring, 5, 10, 86 et seq. 
Mechanics, 18, 77, 231 et seq. 
Medicine, 6, 11, 27, 34, 126, 173 

et seq., 207, 216 et seq. 
Mensuration, 5, 92. 
Mental imagery, 263. 
Mercury, 50, 51, 156. 
Mersenne, 99, 112. 
Metallurgy, 8, 13, 23, 50. 
Meteorology, 122, 133, 158. 
Microscope, 93. 
Milky Way, 144. 
Mill, John Stuart, 256. 
Milton, 102, 213. 

Mineralogy, 130. 
Minute and second, 46. 
Monochord, 17. 
Monte Cassino, 52. 
Moray, 104, 112. 
Murex, 24, 33. 

Napier, 91. 

Napoleon I, 151, 177, 214. 

Napoleon III, 221. 

Natural history, 23, 37, 52, 61. 

Navigation, 3, 16, 26, 54, 126, 


Nebular hypothesis, 147, 150. 
Neptune, 184 et seq. 
Neptunist, 131. 
New Atlantis, 71, 100, 183. 
Newton, 110, 135, 158. 
Nicholson, 177. 
Nietzsche, 277 et seq. 
Nitric oxide, 156, 161. 
Nitrous oxide, 174. 
Novum Organum, 70, 72. 
Numerals, 6, 11, 34, 49, 87, 


Observatories, 4, 49. 
Occupations, 12,51, 58, 68 etseq., 


Optics, 50, 54, 93. 
Organic remains, 126, 140. 
Origin of the sciences, 1 et seq. 
Origin of Species, 201. 

Pansophy, 100. 

Pascal, 95, 117. 

Pasteur, 213 et seq. 

Pearson, Karl, 60. 

Peirce, 195. 

Pepys, 110. 

Petty, 103, 122. 

Peurbach, 55. 

Philosophical Transactions, 109, 

Philosophy, 15 et seq., 134. 



Physics, 21, 28, 31, 32, 50, 54, 
74 et seq., 94 et seq., 110 et seq., 
123, 155 et seq., 170 et seq., 
231 et seq., 245 et seq. 

Physiology, 6, 21, 38, 78, 173 
et seq., 225 et seq. 

Picard, 111. 

Plato, 18, 270 et seq. 

Playfair, 133, 137. 

Pliny, 37. 

Pneumatic Institution, 173. 

Poincare, Henri, 255, 267. 

Port Royal, 116, 279. 

Potash, 23, 51, 179. 

Potassium, 179. 

Precession of the equinoxes, 10, 

Priestley, 126, 156. 

Primitive man, 206. 

Principia, 110, 114. 

Prism, 40. 

Protyl, 254. 

Psychology, 23, 256 et seq. 

Ptolemy, 45, 55. 

Pythagoras, 17. 

Quadrants, 50, 86. ] 
Quintilian, 39. 

Rabies, 227 et seq. 

Racemic acid, 215. 

Radioactivity, 245 et seq. 

Ramsay, 246. 

Ray, 110. 

Regiomontanus, 55. 

Religion, 3, 8, 10, 40, 43 et seq., 

142 et seq. 
Rey, 94. 

Rhind papyrus, 6. 
Rontgen rays, 231. 
Rousseau, 270. 
Royal Institution, 176. 
Royal Society of Edinburgh, 


Royal Society of London, 99 et 


Rumford, 166. 
Rutherford, 247 et seq. 

St. Benedict, 52. 

St. Thomas Aquinas, 53. 

Saturn, 2, 92, 145. 

Saussure, 133. 

Scheele, 156, 180. 

Scientific apparatus, 17, 49, 86 

et seq. 

Scotus Erigena, 53. 
Seneca, 40. 
Shaftesbury, 117. 
Signs of zodiac, 9, 33. 
Silkworm, 109, 221 et seq. 
Siphon, 95. 
Sirius, 4. 

Smith, Adam, 121, 133, 256. 
Smith, William, 139 et seq. 
Smithsonian Institution, 195, 

233, 238. 
Socrates, 44, 117. 
Soda, 8, 51, 179. 
Soddy, 248 et seq. 
Sodium, 179. 
Sosigenes, 36. 
Sound, 33. 

Species, 24, 197 et seq. 
Specific gravity, 28, 36, 50. 
Spectrum analysis, 153, 231. 
Sphericity of the earth, 26, 


Spontaneous generation, 25, 218. 
Sprat, 105, 109. 
Steel, 8, 23. 
Sundial, 13. 
Survival, 206. 
Syntaxis, 45. 

Tables, astronomical, 49, 50, 91, 

185 et seq. 
Tanning, 177. 



Technology, 5, 16, 20, 27, 30 et 
seq., 50, 68 et seq., 86 et seq., 
103, 107, 126, 129, 130, 139- 
41, 156, 160, 167, 177, 182, 231. 

Thales, 15. 

Theology, 47, 62, 172. 

Theon, 46. 

Theophrastus, 26, 39. 

Theory, 30, 41; T. of the Earth, 

Tides, 38, 112. 

Torricelli, 95. 

Trade and trades, 12, 51, 68 
et seq., 107, 115, 118. 

Transformation Theory, 249 
et seq. 

Trigonometry, 46, 49, 55. 

Turgot, 121. 

Tycho Brahe, 87 et seq. 

Tyndall, 260-61. 

Uranus, 184 et seq. 

Vacuum, 95. 
Varro, 38. 
Vesalius, 78. 
Vitruvius, 30 et seq. 
Viviani, 94. 
Vivisection, 38, 71, 80. 
Volcanoes, 40, 136. 
Volta, 177. 
Vulcanist, 131, 137. 

Wadham College, 104. 
Walker, 195. 
Wallace, 211, 231. 
Wallis, 103. 

War, 46, 178, 213 et seq. 
War-engines, 28, 34. 
Watch, 94. 
Water, 157, 177. 
Water-clocks, 13, 94. 
Watt, Gregory, 172, 
Watt, James, 133, 156, 157. 
Wedgwoods, 138, 173, 199. 
Weighing, 7, 10, 86. 
Werner, 129 et seq. 
Wilkins, 101, 104. 
Willis, 104. 
Willughby, 109, 110. 
W T ine, 220, 226. 
Wollaston, 119. 
Wool, 226. 
Wren, 104, 107. 
Wright, 143 et seq. 
Wundt, 258, 259. 

Xenophon, 117. 
Young, 258, 279. 

Zacharias, 92. 
Zodiac, 9, 33. 

Zoology, 7, 12, 21, 24, 25, 37, 
53, 66, 109, 110, 197 et seq. 

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